It's Vista - UAC prompts + MAC bells and whistles = 7.
From what I've read it seems to me the biggest thing in this release will be the suppression of a lot of the UAC stuff. This sounds like a bad idea. UAC is something users should just get in the habbit of seeing. The improved(?) performance will be good, but should have existed in Vista. I think Vista was built just to make everyone buy new hardware
I am going to hold judgement until we see the Vista to 7 upgrade paths and costs.