Mostly good for it's Image Of The Day posting, Flipcode also has some good articles on game design and implementation. Relatively advanced topics and content.

This is the development branch of Flipcode.com. The content is the same style and complexity as .com, but at the moment this is the only one of the two being updated.

An excellent site for articles on every facet of gaming. Regular columns cover everything from design, to management, to contracts, to art. Much of the content is suitable for beginners.