Just some food for throught regarding power consumption: Who bought MediaQ? NVIDIA or ATI? It would be naive to think they aren't going to apply that IP to their next-gen PC/Console parts too, although I'm not too sure about the timeframes tbh. The "cancellation" of the NV50 just makes me more unsure about this. So most likely that's for the post-PS3 generation anyway, but it's not entirely out of the question yet imo.
(this mostly includes dynamically (in hardware) switching off idle units and potentially dynamic clocking adjustements)
Some of those "estimates" are just utopic though eh. Remember we don't even know for sure if the PS3 part is a NV4x refresh derivative or a true next generation part.
Nvidia representatives, including Jen-Hsun Huang, repeated multiple times that the PS3 GPU will be a customized version of their next-gen architecture. ONLY the X-bits labs article based, on Hiroshige Goto educated guesses, mentionned that the PS3 GPU could be derived from the actual GF6 line. It worth to mention that Hiroshige Goto didn't imply such a thing either, on its article on the subject, only X-bits said that (Bablefish?).
And Nvidia bought MediaQ, but that I think you could have guessed it, judging just from the whql reply on the subject.