CS2 but mine seems to freeze up the tools constantly. I don't know what's wrong with it. It works sometimes for over an hour or more, sometimes less than five minutes. I might just switch to CS if I can't figure out what is wrong with this thing.
I have a legal copy of CS, so I'm not really going to bother to upgrade or get an illegal copy of CS2. I heard there wasn't much difference, so I have no ambition to try CS2.