Quote Originally Posted by MecaKane
The PS2 was compatible with all PSX games, so there's so reason they wouldn't be able to make the PS3 compatilbe with what the PS2 can play.
To clarify, there were a small number of PSX games that didn't work, or had issues being played on a PS2. Last time I saw that list was years ago though and only included about a half dozen games, all but one of which I didn't own. FFV in FF Anthology was one of those games and it only had a slight glitch in the save screen that didn't really affect saving at all.

Sony has said there will probably be some games that won't work, but they're doing there best to make as many work as possible. I'd expect the ones that don't work to mainly be unpopular titles. I doubt they'd let games that were actually good and sold well not work for it.

As for Microsofts system, it seems like a bit of a pain to me. I see no reason they couldn't have included compatibility with the full Xbox library at launch, other than rushing things to get it out for the holiday season and ahead of the competition.