I think it will be a bit higher than that. Last I heard, bgassassin was at around 576 GFLOPS (unless those lighting extensions really end up eating alot of transistors) and there was another supposed insider who claimed 600-800 GFLOPS, but closer to 600. Maybe you were reading too many posts from the pessimists?
I agree on you with what the games look like, except I believe 60fps will stay reserved for pretty much the same types of games as they are today - racers, fighters, Mario, etc. For current gen ports, it might be doable, but we'll see. RAM bandwidth could make that an issue.
Edit: Congrats on becoming a member!
Hmm, can you remember who that was?