Yeah, it depends what your need are. Like I said already, from a photographers standpoint, it's definitely worth an U/G I think so too. I think it's way more than what CS2 had to offer over CS, though it's hard to remember CS!
Yeah I agree with that completely, there is very little noticable difference between CS and CS2, however CS3 is quite a bit upgraded with the workspace a ton more easy to handle and flexible.
I use CS3 everyday in my work and i highly recommend it to anyone. It's just the best there is for me.