Damn, everybody likes Cowboy Bebop, Hellsing, Rurouni Kenshin, and Evangelion. I recommend those, but I'll add some others:
Dragon Ball Z
Saint Seiya
Digimon!!! (just kidding
) (I hate it with all my heart and soul, meaning no ofense to anyone of course)
Vampire Hunter D (watched it recently and loved it )
Record of Lodoss War (if you want to see an anime version of Lord of The Rings, there you go
) (Just seen a few chapters, but it's awsome!!! )
Ninja Scroll ( got to love that movie )