Have not bought a PS3 yet but plan on doing it at some point..it always takes a while for good rpgs to appear.
Good thing about it is PS3 doesn't need to be modded to be able to play games from different regions(japan, usa,europe), and as vincent_10_27, I hardly ever use even the existing ps2 for watching dvds...
As for format, I'd tip on Bluray's side, as I see more advantages with a blue laser, and thus with the issue of future compatibility...not sure how accurate that quess is though.
For now the prize/compatibility/reliability of these new HD formats are such that I think I'll stick to old dvds for the time being...
Sincerely, Blanchimont