I did say 'most' PS2 games :P Most of the 'important' ones work perfectly, but a few of them don't. It's nothing that can't be fixed in time with an online update--just like the 360. However, one of the things I'm waiting for before I permanently get a PS3 is for them to sort it out and switch to software emulation (still thinking about getting a PS3 for Virtua Fighter then selling it when it's on 360).
Right now, PS3 has the PS2's physical brains in it to make the backwards compatibility in it work, eventually they are going to move to software emulation. If this happens, there is a small chance of the price dropping a bit, since you're not paying for a PS2 + PS3. They were going to launch the PS3 with the software emulator, but they encountered a mess of problems that forced them to temporarily put the old hardware in there.
I definitely want to have a PS3 eventually, but I'm gonna wait for the emulation before I make my permanent purchase. The VF system will be temporary...if I get it.
That's a pretty weak statement.