2000 A.D. Dredd, Strontium Dog, ABC Warriors, DR and Quinch (Nuke your parents!)
Early Hell Blazer
Eightball (D.Clowes)
Frank Miller Sin City, Hard Boiled, Dark Knight Returns, YEAR ONE (probably the best Batman ever) pretty much all of it (bar 300 and the latest one
)
If you like his RONIN you'll love Lone Wolf and Cub (So epic).
Akira
Mignola's Hell Boy