Such a youngling. I've been an X-fan since 84 when I got my first Annual.
I collect mainly TPB's but will grab some singles every month for fun.
The adult Vertigo stuff is my favourite
Finite series such as..
Sandman
100 Bullets
Preacher
Fables
Swamp Thing
Y the Last Man
Ongoing series like...
Hellblazer
Pre-Vertigo seminal works like
Watchmen
V for Vendetta
I was a DC boy before I was into Marvel so I love...
JLA (oldest comic I have from original series is from 1964)
GL and GL Corps (Hal Jordan was favourite boyhood hero)
Batman (lotsa lotsa Batman
Green Arrow
Legion of Super Heroes
Teen Titans
All the Crisis crossovers (I have the original 12 issues of the original Crisis. Favourite childhood story)
Marvel has become a very large and convoluted universe with often contrived titles IMO so I try to stick to (and get all) the Ultimate Marvel stuff but I do love the stories from their MAX imprint like...
Punisher
Fury
Other Marvel mini series like...
Marvels
Earth, Universe and Paradise X
Inhumans
Non mainstream and movie franchise comics I really love are...
Sin City
The Authority
Planetary
StormWatch (the Garth Ennis penned ones)
Conan (new ones from Dark Horse. beautifully painted stories)
Star Wars
AvP
The Big Books of...
And it wouldn't be right not to mention the comic books that got me into comics as a 5 year old (thank my Aunt mainly for buying them and passing them onto me every month) including....
Richie Rich/Casper/Spooky/Hot Stuff
Uncle Scrooge
The Smurfs
Asterix
TinTin
and of course....
TRANSFORMERS!!!
Few I haven't mentioned but I'll get around to it.