D-gray man (although the series is unfinished due to illness, the manga started up again recently)
Heroic Age
Fist of the Blue Sky (quite violent but has a great romance undertone)
Wakfu (OMG!!! i loooooove this its a french cartoon and its only been fansubbed but i freakin cant get enough of Evangeline she soooooo cuteeee!!! heart an the way she talks is sexy too blaugh )
If you're mature enough, Highschool of the Dead, Deadman Wonderland, Hellsing Ultimate