Kyu 2 Dan
Kyu2Dan is a new Go portal focusing on basically everything that might help you improve your Go skills: theory, tsumego, reviews and professional games are being offered. The content is uploaded by users, checked, approved and then manually added to the site in order to provide high quality content.
Although the site is still low on content, pro-games and beginner tesujis are available already. More content is constantly being added though.