Gran Tourismo, Haze, Metal Gear Solid, Warhawk and Grand Theft Auto should be a good start if you want to justify your decision to buy a PS3. I have one. And I bought it just because I will have access to those games.
However, let me clarify that PSN won't be free forever. That was stated by the president of Sony, so, don't count on the PSN to be free.
Let me add that buying a PS3 was a really good choice for me, I am having one hell of a time playing with it. Games I own, are (among others) Resistance, COD4, Warhawk, Formula 1 and Oblivion. And I play well over the internet. I think that buying a PS3 is a really good choice, since now the devs will take full advantage of the PS3's capabilities, and the XBOX has reached a certain limit (with Halo as a good example).
Does Gran Turismo have a release date yet? As I've said, that game and MGS4 are pretty much the reasons I'll buy a PS3. I'll get GTA for 360. I prefer the 360 controller. Also, I don't mind paying for online at all - if it's as good as Xbox Live is. I'm impressed with the system every time I play online or browse the games, movies, etc, etc.
As others have said, I don't believe the 360 has reached any sort of peak.
I appreciate your post. I want a PS3, but I'll probably wait six months or so before getting one. I'm about to drop quite a wad on a MacPro and 2 ACD's. if they are updated at MWSF anyway.