Of course, we know pretty much that the Xbox will have a G5 in its guts, but Nintendo's (who many consider to be the Apple of the gaming industry) Gamecube-successor, codenamed "Revolution," will reportedly have a 2.7GHz G5, according to IGN.
Check out the fairly long thread on this topic here. It's got 45 posts, over 1300 views, and was started on June 12th. I think it has some pretty interesting comments, and suggest that anyone reading this post check it out.