Scoble frequently posts about Microsoft sites not using RSS. I know it's mentioned in a comment there, but I think Xbox.com is a major candidate for adding feeds. I want:
Right now the closest thing I have is Major Nelson's blog. Come on Microsoft! This isn't technically hard (and even if it were, you're a major technology company!), and there's tons of money in it for you to make your biggest video game target audience (geeks) aware of every opportunity they have to give you their money for things they might want.