Off the top of my head Sanen Naruto fanfic even though I think its abandoned. Dark passions by Azure moonfox WIP Naruto fanfic. Circular reasoning that story get my blood pumping.

 

It's abandoned, so old as to have gotten in on a ton of cliches on the ground floor, and doesn't really ever get going on the overarching plot, but I don't think I'll ever enjoy a fanfic more than Years of Rebellion.

The scope, the prose, the concepts, and the characterization are all just remarkable. It's not exactly subtle, but it's nuanced.

 

YoR does deserve the title of one the best post-OotP fics, or at least past the first 15 chapters or so. FP is not dead, surprisingly, an update to The Last Horcrux was posted a few days ago. Still, I wouldn't hold out for much after two years.

 

My favorite also. Some of my other favorites have already been mentioned: Reign of Power, On the Way to Greatness, VINCET.

Edit: also the Alexander Quick trilogy.

 

I'm going with A Black Comedy like many others and from the Naruto fandom The Tragedy of Repetition by SoulShdw and Fuinjutsu by Eleature are two of my favorites. Although neither has been updated in a while, I still have hope.

 

I'd have to go with Harry Potter and the Summer of Change . It really hasn't aged well, and the writing isn't the best. But even with those complaints its one of the fics that I have most enjoyed reading, and probably my most reread one as well.

 

In the HP Fandom, I've got to go with Wastelands of Time, with Renegade Cause and HPATBWL tied for second place. Path of Decision is in third, but if not for what I feel was a fairly disappointing ending would be in first.

Outside the HP Fandom, One More Hit by Eremite is probably my favourite. It's one of the better 40k stories I've read, including the ones published by Black Library.

 

HP: I loved "The Lie I've Lived" by JBern and "Lost Time" by Amerision but the first story I every really got into was "Litany of Blood" by jon3776 and I'm still waiting for an ending.

Naruto: Hands down Nine Tailed Serpent by LT2000
Eva: Touch by Random1377

Edit: I know wastelands is sort of a site favorite and I really enjoyed it, but I found myself skipping chapters to keep interested. That story needs Roger Corman to be the beta.

 

Song of the Trees and By the Divining Light are my two favorites, closely followed by Denarian series. Sad that Trees will never, ever be finished.

 

Denarian series. Nothing else came even close.

 

Honestly? Probably The Naked Quidditch Match. It's what inspired one the first fics I read and executes it so well.

I think it's really the quintessential humor fic.

 

I wouldn't hold my breath on that one.

Also, content:

Has anyone mentioned "Browncoat, Green Eyes"? It holds up pretty well to re-readings.

EDIT:

Beaten.

 

My favorite fanfic ever is World's Finest vrs The Children of Atom
It's a DC/Marvel Crossover. Pretty baddass in terms of plot, humor , action etc.

Also, the usual suspects : The Denarian trilogy , anything by nonjon.

 

Favourite fanfic ever (that will never be finished): Contemplating Clouds.
It's short, simple and sweet.

There are plenty of more developed romances like C. Night's Inquiring Minds (also never to be finished, and hasn't aged very well) but Clouds just makes me go d'awww :3

As for fics completed/have a chance in hell of completion, we have the epics from all the genres and all of the C2 fics:
Wastelands, Denarian series, BtDL/CS, Black Comedy, etc.

I like BajaB's comedy pieces, especially Two Weeks in the Alley. While it's not uproariously funny like nonjon's material, it has a whimsy similar to what I find in Clouds.
Moreover, it doesn't suck me in entirely for hours on end like the epic length ones so that I can get about my day.

 

Agree with zerg. Comtemplating Clouds by miles.

 

Timely Errors by Wolfe

Not really comparable to some stories, such as Black Comedy or Denarian Series and so on. But, I can honestly say that for pure simple enjoyment, this fic takes the cake. Dunno what it is, but I loved this story.

 

Potters Resistance 1:Breaking ties by IP82

Haven't reread it in a while, but I thoroughly enjoyed it when it was being written. Too bad all signs point to abandoned.

 

In Light Of Silver Memories by Taliath- http://www.fanfiction.net/s/3123807/1/In_Light_of_Silver_Memories

Its unfortunately incomplete and only 6 chapters deep but definitely worth the quick read imo. A spin on Harry with Dumbledores' memories, post HBP, and frankly set my standard for how Dumbledore would act think or feel. The dialog chapter three and beyond is epic. The entire story as short as it is just defines that greater than life epic feel.

 

Favorite fic: Off the top of my head http://www.fanfiction.net/s/6310457/1/bDevil_bs_bAdvocate_b Devil's Advocate. a absolutely amazing Digimon 02/03 crossover.

Favorite HP fic: Another fan of Nonjon's A Black Comedy.