I agree with bsdgeek. The p650 would be a good card for your needs.
OK guys thanks very much. The P650 it is! Thanks a lot for the pointers. I must say I'm rather suprised that people recommend the lower card but grateful in that I can now spend the money on, say, another 512mb of system ram, which I'm sure Photoshop would just love anyway.
I was asking another designer guy on my gaming squad (luckily it's a DX6 2D game hehe) last night what he thought of getting a high IQ card instead of, say, a radeon 9600, and he raised an interesting point: he'd rather have the same quality of picture as the people he is designing for, and so will stick with a gaming card. I certainly have been in the situation when I bring in a design for a client at their office, load up the cd on their computer, gather them all round, go: 'tadaaa!' and it doesn't display properly!
However, I'd just rather have a good card for photoshop. Right now with no gfx card, I'm posting from a 233mhz dell laptop, and it's impossible trying to do anything in photoshop on this; I can use this for testing (and I do) with it's ie5 and low res, but would rather not enforce the experience on myself full-time!
So thanks again for the help, goodness, I am rambling today...
Matrox has a new customer!