Here are some of my favorite comics from some of my favorite writers...I'm compiling a list of graphic novels/compilations that I believe a comic fan cannot go wrong with when looking for something new that they haven't read.

Those titles denoted with a * are must reads if you want to call yourself a comic fan, imho

Frank Miller:
Daredevil: Daredevil vs Bullseye
*Sin City: A Dame to kill for
*Batman: The Dark Knight returns
Batman: Year one
*Elektra: Assassin
Sin City: Big fat kill

Alan Moore:
*Watchmen
*League of extraordinary Gentlemen - Volume 1,2,3
*Batman: The killing joke
From Hell
Neonomicon
Providence

Ed Brubaker:
*Criminal - Deluxe hardcovers 1&2
At the seams
The Fade out

Warren Ellis:
No Hero
Transmetropolitan Volume 1-10
Hellblazer - paperback volume 13

Garth Ennis:
*Preacher - paperbacks 1-9
Goddess
Hellblazer - paperbacks 5,6,7,8 (he wrote most)

Neil Gaiman:
*Sandman - paperbacks 1-10
The books of magic - paperback (one with original comics 1-4)

Greg Rucka:
White out
White out:Melt

Brian Azarello:
*100 Bullets- Deluxe editions 1-5
Hellblazer - paperback volume 14&15

Mignola/Byrne:
Hellboy: Seed of destruction
Hellboy: The Crooked man

Robert Kirkman:
*The Walking Dead - Hardcovers 1-11

Paul Chadwick:
*Concrete - The complete concrete

Joe Hill(Stephen King's son):
Locke and Key- Hardcover 1-6

John Wagner:
Judge Dread: America