Nintendo has only said that their Revolution will be affordable, and nothing else. That's what I've seen so far, anyway. On the other hand, Playstation 3:
http://ps3.ign.com/articles/615/615745p1.html
And then:
http://ps3.ign.com/articles/618/618540p1.html
I get the feeling that the former of the two is what will happen, though. Especially if X-Box 360 is also going in the $450-$500 range.