I approve on Koby's suggestions Having seen D.Gray-man, Ninja Scroll, One piece, Death Note, Code Geass and some of Black Lagoon, I'd recommend those too. You might like Fairy Tail too (its fairly recent in anime).
Currently following on Naruto Shippuden and Fairy Tail - and I just finished D.Gray-man too (and I soooooo hope they're gonna keep up the anime once the manga series is over....)
Wah ! There's just so many anime I like O_O - I'd say Naruto Shippuden is currently my fave although pretty close with D.Gray-man, but I just can't get passed Cowboy Bebop or Escaflowne (so much souvenir ! XD)