I need some recommendations as well...
Here's what I own now, although I used to love Dark Horse, but after my old collection was stolen, I never could remember half of their stuff I liked besides the licensed material...
BATMAN: The Long Halloween
Godzilla: Color Special
Sin City: Vols. 1 - 5
Ultimate X-Men Vol. 1 (Softcover)
New X-Men Vol. 1(Softcover)
(definately plan on getting the rest of this series)
Ultimate Spider-Man Vols. 1 & 6 (Softcover)
Venom Vols. 1 - 3
And while I love the cool artwork in the Ultimate lines (minus the way they've "updated" the Spidey villains), I can't stand the changes that were to made to the Venom story... So fire away