Sony won't be doing a simultaneous world wide release and didn't the PS2 come out here a year after Japan? I am definitely betting on 2007 for the PS3.
I don't believe there will be much difference in performance between the two consoles. At the end of the day multiformat games are always designed with the least powerful console in mind. Hence why Xbox owners currently get lumped with PS2 looking games yet exclusive titles or PC conversions are a heck of a lot better. If PS3 is a lot better than 360 the situation will be reversed and PS3 owners will be stuck with games designed to run on the weaker 360 platform but with a few extra special effects chucked in as compensation. Of course they will have their exclusives but there will be less and less exclusive games this time round due to the high costs of development and developers needing to make as much money as possible to break even.
I'd expect to pay a lot for PS3 extras like HD's. Remember how much the original PS2 memory cards costed!!
I don't rate Sony, I was a massive PS1 fanboy but the PS2 was a bit of a sh*tbox and let the side down. You had no in-game 5.1 support (I mean FFS that is prehistoric) and you had the problem with RGB turning DVD's green forcing you to have a special scart lead with an RGB/Composite switch. Who the f**k designed that?!?!?! They couldn't even get the basics right! Of course ask your average PS2 owner about that and they won't have a clue what you are on about as they are mostly dumb a**es that just use the packaged lead and think it looks fine!!!!
Same goes for the lack of a 60hz mode and those nasty borders. That just about sums up who buys PS2's and who they are aimed at.
Sony have announced that there won't be an Xbox Live style service for the PS3. With similar graphics and both consoles pretty much equally supported by third parties I think the user friendliness of the online system will be the killer and XBox Live is absolutely superb. That pretty much kills the PS3 off for me although I expect I will still buy a PS3 purely because I can afford to and it will have a couple of exclusive AAA games. I had a PS2, Xbox and Cube by the way but the XBox was the only one I kept.