Aside from shameless plugs, I will also add in Anime News Network and Animaxis, which is where I get all my anime news up to date from, and for my J-Pop information and purchases, CDJapan.
I guess Japanese Channel is a J-Pop site...I thinks its more of a J-Rock site, but its still my fav. Gackt and Hakuei are on it so it made me happy ^_^
for mang mine is http://www.mangacity.net it has scanlations for Gensoumaden Saiyuki. I don't have a favorite anime site because there's too many unless u want to count the sites I buy from.
Animenfo.com which's been mentioned before and
http://www.animesuki.com
This site provides links to non-licensed anime in America (warning: requires Bittorrent to download the episodes, you can grab it here: http://bitconjurer.org/BitTorrent/)
If you know Chinese｡｡ and you like manga
this site is your best choice, you can read manga online｡｡
http://www.gggate.com/comic/home/type.asp?typeid=17