Hmm, depends on the genre I suppose. I love cyberpunk and sci-fi anime.
Bubblegum Crisis (including Total Crash, Parasite Dolls, A D. Police, and 2040). The original series is super 80's mech suits with glam and hair metal.
Ghost In The Shell: Stand Alone Complex
Texhnolyze
Serial Experiments: Lain
Blame! (I love Tsutomu Nihei)
Knights of Sidonia (also Nihei)
Welcome to the N.H.K.
Planetes (sci-fi drama)
Vampire Hunter D and Bloodlust
Edit - I tried Castlevania but couldn't stomach it for some reason after seeing the early bar fight scene.