Comics is the most appreciated form of culture for me, and it has been for as long as I can remember. The easy access to "adult comics" via second hand shops was an excellent way to experience transgressive culture at an early formative age. So I've grown up with a keen interest in both mainstream and alternbative comics. I have probably spent more money on graphic novels and comics than I have on any of my other major interests, including music and film. In fact i like it so much I only really dislike syndicated comedy stuff...
The access to good anthology magazines from the late eighties and early nineties gave quite a broad spectrum of styles.
I'd say my personal favorites are
The classic proto-Vertigo writers and titles like Grant Morrison (the Invisibles and the Filth being his finest, but also New X-men, 7 soldiers of Victory, Zenith and Doom Patrol being almost perfect), Alan Moore (V for Vendetta and Swamp Thing being my favs, of the late stuff I'd say Promethea. Not so keen on Watchmen though), Hellblazer in most incarnations (the original Delano run being the best, followed by Mike Carey and parts of Garth Ennis run, especially Dangerous Habits and the one where a demon possesses Prince Charles), Milligans "Shade the changing man" was also fantastic most of the way through, too bad most of it remains uncollected. Too bad his take on Hellblazer has been a real underachiever, just like his incredibly boring X-men stuff.
Warren Ellis - I think Transmetropolitan is quite fun, though I like his "Silent City" the best. Planetary was good (and the art was excellent). I also enjoyed his early work on the Authority, before he left and it slowly degenerated into shit.
On the other hand I can't stand Preacher. I never understood what people see in it. Silly, tedious bullshit where everything just pushes too far to be "badass" until it just becomes unbelievably ridiculous, and not in a fun satirical way but just... Perhaps I should give it another read, as I went through it all about ten years ago and never looked back. Maybe I could get into it this time (and I really don't like Dillons illustrations. I don't think he's bad, he's talented indeed but I just don't find it enjoyable. it's like manara, skilled but he only manages a couple of sets of faces, boring. Good at drawing jaws being blown away though).
European sci-fi and art comics(the genre of true masters); with Phillipe Druillet as my absolute no one, followed by other classics - Moebius, Caza and Bilal. Liberatore/Tamburini. Adamov/Cothias. Nazario.
American alternative comics have also influenced me a lot, especially S Clay Wilson (he's a god!), Julie Doucet and Jaime Hernandez Locas, a soapopera with just the right mix of surrealism, social realism, sex and slapstick to make it perfect. Always preferred him before his brother though I've understood many are more fond of Gilbert. Michael Manning is also an excellent artist, perhaps not storywise, but his artwork is fantastic.
My guilty pleasure no one is superhero comics, despite it being quite crappy most of the time. I got into comics reading Claremonts X-men in the eighties and his mix of soap and generally pessimistic stories (everything was going quite bad all the time) and the pseudofetishist details really made an impact at that young age. I never quite let go of it, though most of it IS horrible.