Batman (I loved how the writers started making the stories more intense by the 90's, especially The Joker, and then Bane breaking Batman's back).
The Tick (I used to have the first few issues when it was new. It was funny as hell in the beginning. The cartoon disappointed me though.)
Lobo (What a sick bastard. His dialogue was hilarious. His appearence and attitude reminds me, in hindsight, of Lemmy Kilmister from Motorhead) "Bite me Fan boy".
Spawn (We all know Spawn).
Judge Dredd (I wouldn't have known about Judge Dredd if not for the band Anthrax and their song "I am the Law", which is based on this character. Judge, jury and executioner, he is. The Sylvester Stallone movie didn't do the comics justice (no pun intended) - even Stallone has said how bad it was. However, a new movie take is in the works, due to be out next year, titled "Dredd", this time with the participation of 2000 AD (the company that publishes the comics) and the comic's writer/creator, so it should stay much truer to the comics and the character. It's said it'll be darker and gloomier, and it will be in 3D).