I ran Photoshop on an old G3 300mhz, a 5 yr old thinkpad and before all of those, on a Powermac 8500. Sure, Photoshop has gotten bigger and more powerful since then, but your MBP with 128 GPU should have no trouble with most of what you throw at it in the real world. There is always a more powerful machine out there, but it doesn't mean you can't get work done with what you've got. Otherwise, how the hell did we ever exist 10 years ago? Just match the right software with the machine, and you can run old computers and still do amazing things, if you have to. Some of the graphic design and photography and magazine design work we did over a decade ago was pretty damn sick, even by today's standards. So, keep it all in perspective.
Of course, all the latest, fastests CPSs and GPUs and hi-speed busses and super-fast HDs and gazillion GB ram will always perform operations faster. That's always going to be the case. So what? Is what you can get
now able to do what you have to do,
now? Then don't worry. Be happy. Get busy.
BTW, I've got the MBP SR model, 2.2 ghz with 2 mb ram and the 128 mb gpu. It works just fine. I love it, and don't even stop to think about what I could have instead. I just get stuff done!