phew....this could take a lot of space if I listed everything. Instead I'll post a few of my favorites and what I am currently reading.
My favorite of all time, as you can tell by my avatar is Scott Pilgrim, and he is an manga character as he's appeared in other manga.
anyways I'm also a huge fan of Full Metal Alchemist, Love Hina, Negima, and Rosario + Vampire,
Several that I am currently reading are Bleach, Ao no Exorcist, Cage of Eden, D-Grayman and Fairy Tale.
This just names a few, I read a lot of them, though I'm always open to new manga or anime, so please let me know if you recommend any.