I do Death Note! Team M&M (Mello and Matt)!
Some of my favorite books/series are:
*The Black Jewels Trilogy /related books
This series, by Anne Bishop, is awesome. I guess they'd be rated M for sexual content, violence, strong language and super awesome characters. The first trilogy is 1204 pages, and I've read them like four times. There are also side stories that go in between the books (and before), and it's still continuing!
Also by Anne Bishop is the landscapes of Ephemera, there are two books out and I'm hoping for more. It's a little confusing at first but once you understand it's very cool. It has succubus(es?), an awesome antagonist, lots of death and even some romance! These series are both fantasy.
*The Obsidion/Pheonix Transformed Trilogy
By Mercedies Lackey and James Mallory
These series I put under one category because the second one (Pheonix) takes place almost a million years after the first one. It's more midevil, with elves, unicorns, dragons, the Endarkened (demons) and the whole shibang. There are two different types of mages, too. But it's not as corny as it sounds. This is my favorite series EVER. If you like fantasy, check out both of the series I've mentioned.
For mangas I like Deadman Wonderland, Mix Vegitables and Vampire Knight. The animes I like are Death Note ( as said earlier), FMA, Inuyasha and Spice and Wolf. Once I think of some more books and manga I'll post again!