When the Hat was first introduced and opened it's mouth in Jbern's The Lie. Hilarilty ensued. It came out of nowhere, too.
That's the first that came to mind.

Edit: Reading The_Substitute by BajaB. Fuck. That. Shit. Really shook me when I first read it, and every time I re-read it.

 

Denarian Trilogy (also by Shezza, the story whore). Graveyard scene, story one. Harry picking up the Sword of the Cross and smiting Voldemort, and becoming the first Denarian host to also be the very thing they fight against. And then, being introduced to the mind fuck that the Fallen Angel itself was the Knight (two stories later!), and not Harry. Fuck.

 

When I read the Hero Trilogy which honestly isn't well loved by people not named Alec, because most people think it's mediocre. It falls into a lot of Indy! traps but I never quite saw it as being just another indy fic. Something about the story just hit the right chords all the way through the trilogy. once I started reading that story, I didn't stop for the 6 or so days it took me to read every chance I got.

And then I found Wastelands.

So Joe sorta kicked ass (and I just saw he's viewing the thread...).

Other moments would definitely be the intro of Hat in TLIL, the first time I read a fic that wasn't Harry/Ginny at about 13 and realized there was so much more stuff to read, and 2 years ago when I found Renegade Cause and started reading it figuring it was another story I'd toss after the first 5 chapters and instead found myself completely hooked.

 

Chapter twelve in Yellow Submarine, specifically where Ginny screams "you're balding!", and all the connotations that has in the fic. I've read the fic a few times, and I still get a slight shiver, because I hadn't expected it at all the first time I read it, and it felt like it came from near nowhere.

Chapter 16 in Darkly Dreaming Harry. Hagrid shouting at the centaurs -

 

Reading my first Indy! Harry fic, the Legacies series by TheDarkLordNedved. It was the first time I found fanfiction, and that fic still remains one of the most memorable in my memory. My tastes have also changed a lot over time, but if there's one story I can read any time, anywhere, it's that one.

Plenty of memorable scenes, my favorite being the final fight between Harry and Rudolphus' army, when Harry has to kill an imperius cursed Hagrid. I also loved the rivalry/comradeship thing between Harry and Malfoy in that story.

Also, Jono's Stranger in an Unholy Land, and TheJackofDiamond's Harry Potter and the Hero's Path.

 

For me, the two most memorable scenes in fanfiction both come from Stranger in an Unholy Land.

The first was the Death Eater attack on the Hogwarts Express, Harry kicking arse on the train without knowing how or why.

The second was when Voldemort took the Ministry after allowing himself to be arrested. This remains for me the crowning moment of fanfiction. This was well before DH was released. It was the first time I had seen anyone have Voldemort execute a successful coup, rather than just have him perform endless mindless attacks on civilian targets like Diagon Alley and Muggles. It was stunning.

 

In Summer of change when Harry nearly kills the Dursleys with the killing curse and he's talked down from it by Tonks and McGonagall. The image of the killing curse swirling around his wand was just so damned cool.

If I read that scene now I'd probably facepalm.

Another more recent one is Harry's experiment with Aqua Eructo in a massive rainstorm in Harry Potter and the boy who lived. A great piece of imagery.

 

Has anyone thought of this piece of shit recently? All honesty though Scorpion Sorcerer is one of the first fics I ever read and is probably responsible for hooking me on FF. I tried to reread it maybe three years ago and couldn't make it past the first chapter.

However the one moment I always remember is when Harry and Neville threw down with Dumbledore. Every other manipulative Dumbledore story is all just talk and whining about how mean Albus is. Whenever I read about some shitty Dumbledore9000 that has monitoring charms set up on every toilet in the school on the off chance Harry may decide to visit one that scene springs to mind.

 

Lol, Scorpion Sorcerer will always be the ultimate in Indy!Harry long summer training fics. The whole story is essentially one big training log. Some parts of it read like Exodus.

...and you shall build a magical trunk, and it shall measure five cubits by two cubits, and it shall be made of acacia wood. Its handles shall be made of gold, and upon it shall be a time dilation charm.

 

I think that several duels in The Serpent and The Phoenix totally qualify, as well as Harry's awesome trials, and the greatness of Danny Oaks more or less going "wait... wtf" when Harry comes back.

Spoiler

and the whole death of dahlia bit because HOLY FUCK!

Story is old so spoilers may not be necessary but not that many have actually heard of it /hipster.

 

The first part of Tears of the Phoenix, Hermione's monologue. Don't know why, it's just always stuck with me. I think it was the first or second fic I read also.

 

I've got five that really stand out for me in terms of fanfic, at least off the top of my head.

Strangely, the first two are actually linked to a ship I really dislike, H/Hr, and both take place in fics with that ship.

The first is the airplane explosion scene from Harry Potter and the Fifth Element. Up until then, the story had been progressing at an agreeable pace, and things were going reasonably right for Harry and his relationship with one of the most likeable OCs I've ever read in fanfic - and then they get high and are about to fuck and suddenly WHAM. In all due honesty, between the build-up and the downright terrific atmosphere building that occur in those two scenes, it pretty much almost justifies the entire story right there, and the fact Bexis was able to sustain the tension for the next chapters was pretty damn amazing.

The second moment occurred with the end of Unsung Hero. It was the first time I had ever gotten visibly angry at the end of a fanfic. It was such a fucking copout, and it didn't fit the story at all, and even despite everything that I hadn't liked in the second half of the fic, I was prepared to overlook it - but the ending crossed some sort of line for me. I could spend an hour ranting on why it failed and utterly destroyed the story and any poignancy it might have. Talk about absolutely infuriating - I actually had to go take a walk after I had finished it to cool down, I was that angry.

The third moment is strange, in that it's a real moment of anti-climax that I remember getting me really annoyed, and that's the ending of the R-Series. Having trudged through seven stories (and the last two-and-a-half were really a struggle), I reach the ending and I feel as if the stories should have meant so much more than they did. It was a feeling of such emptiness, of such a lack of pay-off, that for all of the work Regulus put into his story, good and bad, the ending just was painfully weak.

The fourth is also a strange one, at least in the context of DLP. It's from the Glee fanfic Just Like Last Tuesday, Except With Zombies, and it comes after a certain character gets infected by a zombie bite, and that character is then killed by one of the other survivors. That moment was poignant enough in and of itself, but the conversation between the killer and one of the main cast right afterwards is so stark, and honest, and has so much feeling in it - it's surprisingly powerful, coming from a character that never showed any signs of vulnerability at that point.

The last one was the Tessa sequence in Wastelands. Anybody who has read that sequence gets it. Nothing more needs to be said.

I'm sure I'll come up with more, but those are just the ones on the top of my mind.

 

My biggest moment is in an old Wheel of time fic, Black Flood: Tales of the Trolloc Wars. It's about the fall of Manetheren at the end of the trolloc wars, and the last few chapters as the city falls will always stick with me. Particularly the last chapter as Eldrene destroys the city.

My second one is more recent in Incorruptible by Matt Silver. I'll give it spoiler tags as it's a recent story.

Spoiler

The scene where Harry arrives at Malfoy Manor to find Astoria dead. Harry's reaction as he works out what happened before finding the body and reading her note. It was so brilliantly written that I really felt for the characters.

I just didn't see it coming.

 

Oh my god this, the whole fic had me going, but that and

Spoiler

the scene where Juliet killed Terry

really got me on a deeper level. Incorruptible had me incredibly emotional, and it's rare that even a very good fic gets a tear in my eye but this one did several times.

 

What is in a Soul has almost the same idea as BajaB's and at least for the first chapters is emotionally tearing. It makes you even wonder about the philosophy behind what happened. At least for the beginning it's worth reading.

One of the moments I will remember forever is in Joe's Defiance of the Hero when he rides on his horse on the last few meters before he arrives at the end of the path. That was a film worthy picture and you really felt with what Harry went through to arrive there. Something like the Old Man and the Sea. Too bad the rest of the story shows its age/length when rereading it.

 

I think with how iffy my memory is lately and the sheer volume of how much I read I just have to add that the line in Defiance about staying a virgin for a century because of Ginny is memorable, mainly because it's sort of silly and sort of sweet.

Also the Padma romance plot (unless I'm thinking of the wrong fic) was totally awesome, but it shouldn't have died.

 

Right now I remember two moments. The first one is the whole experience of reading Survivor. It's HP/HG story from Ron's perspective, where she dies at the beginning and the rest is about Harry living long enough to get the revenge and then joining her. In other words a big angst fest that I normally avoid, yet at the time I decided to read it, because it was quite good and had likable Ron which wasn't a usual thing.

By the end of it I was almost crying (to this day the only thing in fiction that actually made me cry was the death of Optimus Prime in The Transformers: The Movie, but that was almost twenty years ago ), because the author really managed to sell this atmosphere, instead of making me cringe about how overly melodramatic it was.

The second moment was in AU fic from Naruto. It was one of these stories with characters living as normal people in the world like ours, not to mention they only share name and basic traits with their source counterparts. Actually, with so much changes it could work better as an original story, but you know how it is.

Anyway, in this story Hidan was a priest and Tobi was a barman. They have a interesting talk about the God and responsibility of serving him, but it was other thing that stood out to me. It was a part describing how Hidan sees Tobi as a man "who loves people in spite of their flaws or perhaps because of them".

It's nothing original, but for some reason it made me rethink everything about this type of characters that always see the best in people.

 

To Fight The Coming Darkness

Serious story that had me laughing at several points. The story itself was awesome but the moments with Wormtail make it worth going back and reading them... It was also the first time I read Harry use the killing curse and I was like, "What a bad-ass!"

http://www.fanfiction.net/s/2686464/9/To_Fight_The_Coming_Darkness

The conversation between Wormtail and Voldemort about being a successful Death Eater is too much... Not to mention Wormtail is in the middle of turning Percy into an Inferi. Then there is also this...

"See I told you nothing ever changes. Same old Wormtail!" The boastful voice of Walden McNair shouted with his crooked teeth grinning and an eye patch over his damaged socket. Voldemort planned to make the gift of Alastor Moody's eye sometime tomorrow. It was ironic that Peter had been detailed to locate the vision specialist to adjust the eye to Walden. Peter simply glowered back at the large man.
"So, little rat. Are there clean linens in my room? Did you remember to leave a mint on the pillow? I need a wake up promptly at 7 AM," McNair continued. Several of the others laughed. Rookwood was laughing so hard that he was gasping for breath. Voldemort was interested to see what Peter's books had taught him about confrontation.


Peter looked up. Everyone assumed the redness on his face was from embarrassment and not from anger. They were all wrong.


"What kind of wizard are you, McNair? Who names their child Walden to begin with? A mother who does not expect her child to go far? Perhaps a father who realized he did not pull out quick enough? I digress. I do recall you being outsmarted by a hippogriff recently. True, it did have the unfair advantage of being chained to a post at the time. What kind of wizard uses an axe of all things to kill something? Are you that magically feeble? I would go so far as to guess that you were the weak link at the ministry. Which one of the children incapacitated you? Probably the weakest among them."


The room was utterly quiet for a moment as the two stared at each other. Voldemort allowed a thin smile at the looks of shock from his inner circle. The silence ended with both men going for their wands. Peter's draw was flawless. Walden's in contrast was rusty.

The duel was short and simple with Wormtail winning, but that little passage has provided many laughs.

 

There was this old, really short story but it has a pretty sweet passage that totally sold the idea of Harry/Luna to me.

Spoiler

The thoughts of the prophecy, the war, and Sirius, had all but left his mind for the first day in along time. It didn't feel like this girl occupied the same dark world he had suffocated in during the summer, somehow. She seemed almost like a star, some beacon of hope, that shone above these things, and although she could not make them go away, she was something to look for in the darkness surrounding him.

-From "Loathsome Lobster of Leeds"