My favorite anime, hm? Well...
5. Sailor Moon (First Season)
4. Angelic Layer
3. One Piece
2. Naruto
1. Laputa (Castle in the Sky)
Manga is a totally different story, since most of the manga I love I haven't seen anime for:
5. Cardcaptor Sakura
4. Psychic Academy
3. Fruits Basket
2. Hikaru no Go
1. Kaze no Tani no NAUSHIKA (Nausicaa of the Valley of the Wind)
Nausicaa is so breathtaking, I can't believe it wasn't more popular. I'm a big fan of Hayao Miyazaki's anime, but this, his only manga, is by far my all-time favorite, and that's saying something, since I own over a hundred different series (most of which are still running, lol). Not only was this one one of my first, but it was forever the best. If you've seen the anime, you haven't seen even half of what Miyazaki has done with it, and you've only gotten a taste of its treasures. Anyway, I'll stop harping on that and let someone else tell their faves now. :P