Well, I can certainly be a proponent of necromancy when it provides reading material for the next couple of weeks!
And as thanks for all the contributions, I have some of my own. Most of the things on my lists tend towards Harry Potter or Naruto simply because of the quantity of those fics you see on FF.net, but I'm bringing you a much wider range than that today.
Harry Potter
Action
Anything by
JBern. Note that Bungle in the Jungle and its sequel Turn Me Lose are both written in 2nd person. Even if that's slightly off putting I suggest you try BitJ before giving it the axe, he used that project to actually publish a novel (Deadeye).
Humor
I am
surprised that
A Black Comedy by nonjon hasn't been mentioned yet. This is one of my all time favorite fics, and it is complete to boot.
Dark
Last but not least,
Anything but Slytherin is a one-shot by IP82 that asks what could happen if the Light side were a little... less... light.
Naruto
Death's Precipice is a Lee-centric story on feeling the death god's hand on your back. The Sh33p is a pretty bloody good author to boot, one of his other fics I'll also stick in the Superman section but most of it is top rate.
Death of a Kage Bunshin is a Naruto-centric fic written by Foxie-sama, who also did "For the Love of My Friends" (which is considered one of the first fics in the Time Travel fanon for Naruto, and one of the most recognized). The one shot is far more satisfying though, as FtLoMF is over 500k words and stalled out at the end of the Chunin Exam arc.
Lastly, your mileage may vary on this one. I really enjoy pretty much anything written by
Case13/Fosfor, but a lot of people don't. If you
do, he posts semi-regularly over on Hawk's Fanfiction Board (TFF) and has more work over there.
Discworld
A lot of samvimes's work is good, but I'm going to have to say that
Some Buggers is the best piece of Discworld fanfiction he's got. It also has the (somewhat dubious because I don't go looking for it much) distinction of being the best I've ever seen, it reminds me of Pratchett's work quite a bit.
Superman/JLA
Probationary Member is a bit of a hit or miss. I read the beginning, got bored with the middle, and skipped to the deeply satisfying (if sad) end. Worth reading if only until you get to the "big reveal" of who the Batman is sponsoring.
Imagine That
"In which the most obvious fact of Superman is that he's not."
Read it, seriously. A fairly short one shot that you
will not regret.
Doctor Who
There are a great many Doctor fics out there, just not many that are any good. Even the most interesting fic seems to slip out of character and into something (pointless) else. This is... distressing, for someone who was only introduced to the series with 9 and 10 and is trying oh so very hard to work his way through the rest of the mythos.
However.
If you are a 10 fan, or, dare I say... a Master fan. I would recommend
And From Thy State for a terribly satisfying take on the character's thoughts.
FFVII/Kingdom Hearts
But That Was In Another Country is the telling of FFVII falling to the Heartless from Yuffie's point of view. This fic is
very dark, almost too much to read in a single sitting. It remains one of the finest FFVII fics I have ever read.
Death Note
Maybe its just because I haven't looked enough, but
Redivivus by Silver Pard is the only quality Death Note story I've ever found. Well written, interesting, and best of all... the author actually understands how to write L/Light!
>> Oh don't look at me like that, hear me out.
Anyone that has read Death Note probably understands that there is something between L and Light. A connection, deeper than anything romantic or sexual. The by-play between the two characters literally made the series, I know many people who lost interest entirely after the world's greatest detective was killed. Silver Pard brings that interaction out in Redivivus to the point where it feels like you could actually be reading the series again. So while it may lean towards M/M, don't let that put you off an excellent story.
Ranma
Ozzallos is usually my go-to guy for quality Ranma fics, both normal and Fuku flavored.
Heir to the Empire is a complete Fukufic, but the rest of his work is well written too. A Time Apart is promising, but fairly short at the moment.
On the other hand, Gaming Ikari's
I Was Right All Along is straight Ranma, told from Ryoga's point of view. Like much of the quality writing I'm recommending here it is a bit dark.
Taking things a bit further...
Ill Met By Starlight is an
extremely dark fic. Brilliant, yes, but...
Well, to each his own yeah?
I think that's enough for now.