dale, the main movies will always play fine as the codecs are fully supported. The profiels apply to special features. Sony reps have said this here and there, I just can remember where I read it. Either way I bought a PS3 at launch just because I knew it was upgradedable, and the games of course.
I know this is old but I'll reply anyway since no one else has, I just found this site. The 2x Blu-ray drive in the PS3 cost $300 at launch, now it's more like $200 or lower.
Blu-ray gives the PS3 an edge in a lot of areas. Game devs are actually able to cache data straight from the disc. Games like Uncharted show of the potential of Blu-ray. There are no load times what so ever. Furthermore games no longer have to be split up or downgraded in quality. Project Gotham Racing 4 did not have night & day tracks because of a space limit. The developers have the room (50gigs) to put in what they want. And it’s cheaper as well; you can fit all of the languages on one disc. And since the PS3 hardware is region-less a company can literally just press a single copy a million times over for all regions. And finally no disc swapping required. On the 360 Blue Dragon is 3 duel layer DVDs while Lost Odyssey is 4 duel layer DVDs.