My favorites, based on stories and works I’ve enjoyed (mostly for my own archival purposes):

1. Alan Moore (Watchmen, League of Extraordinary Gentlemen, V for Vendetta, Batman: Killing Joke)
2. Geoff Johns (Green Lantern, Infinite Crisis, 52)
3. Frank Miller (Dark Knight Returns, Batman: Year One, Sin City, 300)
4. Grant Morrison (JLA, Seven Soldiers of Victory, 52, Final Crisis)
5. Brian Michael Bendis (Avengers Disassembled, Secret Invasion)
6. Judd Winick (Batman: Red Hood)
7. Mark Waid (Kingdom Come, JLA, 52)
8. Alan Grant (Batman)
9. Brad Meltzer (Identity Crisis, Justice League)
10. Kurt Busiek (MARVELS, Astro City)
11. Jack Kirby (DC Fourth World)
12. Larry Hama (G.I. Joe)
13. Gerry Conway (Justice League)
14. Jeph Loeb (Batman: Long Halloween, Batman: Hush)
15. Gail Simone (Villains United)

Alan Moore’s Watchmen is the best comic series ever. I just wrote an essay about it for my Liberal Studies class. Frank Miller co-directed the movie adaption of his comic Sin City, which turned out to be the best comic book movie ever. He also wrote 300, which is another great movie. The rest of them you probably wouldn’t have heard of before unless you’re into comics.