So. damn. hard. Here are eight that haven't been mentioned above:
Ides of March by
finding_jay
H/W, R. This one shocked me and left me in awe. Absolutely arresting.
Irreversible by
kribban
H/W, Adult. Incredibly powerful. Not a deathfic, but read the warnings if you find certain content disturbing.
Reservoir Docs by
rivers_bend
H/W, NC-17. Gun!kink with a hint of danger but no violence.
Including the Kitchen Sink by
genagirl
H/W, PG-13-ish. Crackity-doo-dah that makes me laugh.
The Annals,
Part 1,
Part 2,
Part 3, and all parts written in the future, by
Nightdog
House-Wilson friendship, PG-13. House and Wilson in Roman times. AWESOME.
Eos's Lost Causes was already mentioned, but the deal is sequels too, right? So I'm also going to take Same as It Ever Was, Reverse Psychology, and Foolish Hearts. (All found
here.)
H/W, PG-13. A long wonderfully IC story chronicling the evolution of the stupid, screwed-up friendship into something very much more.
Zombie fic! by
triedunture
Unrated (R?). With a name like that, it has to be crack, right? Except it isn't. Taut, suspenseful, great use of characters, and not one thing gratuitous.
Three Corners by
fallen_arazil
(I also get to bring
Evening In, because that's a missing scene)
H/W/Stacy, NC-17. A lovely, long what-if, from pre-infarction to just post-infarction.
Episode: All In
Note: The only reason Asynca's Essential Elements of Teamwork and Eggshells aren't on the list is that I'm betting one of you fine folks will include it.
PS.
CTL, wow - Out of the Blue in your top eight? Thanks!