I'm a big fan of Jeff Smith's Bone, Stan Sakai's Usagi Yojimbo, James Turner's Rex Libris, and Paul Chadwick's Concrete.

"Hicksville" is probably my favorite but "I Killed Adolf Hitler" gets better with each reread.

Bone, Cerebus (if you want specific chapters, "High Society," "Church & State," "Jaka's Story," "Guys," and sometimes "Melmoth"), New Frontier, Sale and Loeb's Batman/Halloween stuff, and From Hell. Tho not necessarily in that order. And, tomorrow, the list could be different. (Like "Selina's Big Heist." That's a good one. And "Avengers Forever.")

(But (to put a finer point on it) a novel is a novel is a novel. Dunno what that "graphic" business is all about...)

This isn't my favorite, but I read Whiteout this weekend and loved it. Very few books successfully transport you to another world, but this one does.

I forgot "Watchmen." That's a pretty good one.

Blacksad

I'm going to have to go with DKR.

Funny you should mention him, since I have such a soft spot for the Dream Corridor trade... (SF/Sci-Fi)

The Checker Clive Barker reprints (Hellraiser and Tapping The Vein) still make me smile as well. (Horror)

I adore Watchmen, but some of the elements (the pirate story, all the suplemental material) is a bit of a distraction...(mystery)

Lapham's Stray Bullets and Murder Me Dead get honorable mentions, (crime) as does JV's JTHM and Squee, (comedy) what I've read from Eisner, (classical lit?) and most the Veritgo line up (everything else). (runners up)

For superheros, I guess the Essential Spiderman Vol. 1 still holds up... Marvels and Kingdom Come are real nice to look at.(d'uh)

I want to say Gaiman's Stardust is my favorite; though even with Vess's art, it's still an "illustrated novel" at best. (fantasy)

There was a Jimi Hendrix bio by Greil Marcus and Skienewitz(I can never spell that guys name) that I really liked...(also d'uh)

I could probably keep going and invent a few more genres; but the truth is I most likely don't even have a favorite, except what I'm in the mood to read at the time.

A great series of graphic novels / albums: Dungeon (or Donjon in the original French). Masterminded by Lewis Trondheim, this is a series of fun, humorous stories set in a D&D fantasy world. Art duties get handled by different cartoonists for different albums, but they have all been of uniformly high quality.

The series is projected to run to a hundred volumes or more eventually, covering the past, present, and future of the world, the stories of the main characters, side characters, and so on. They have published about a dozen or more albums in English so far, from NBM. It's fascinating to see these highly independent cartoonists apply their skills to a popular, big-studio-type endeavor like this.

Highly recommended, but one note: despite the cartoony art, the stories do have some sexual and violent content in some volumes, so they're not all for kids.

See more at the NBM Dungeon web page.

From Hell
Ghost World
Louis Riel
Ice Haven
Diary of a Teenage Girl

...that would probably be my top 5 at the moment.