Welcome aboard and thank you for your contribution.
Well you basically have two options:
1) install 1 or 2 regular clients probably worth 200-300PPD each
Advantages:
Very easy installation
Run as service
2) Install the SMP client probably get 1000PPD
Harder install
Much harder to run as service, though not impossible
For 32-bit OS's, you would run the
DEINO version of the SMP cleint.
BTW don't forget to run the client with the "-smp -deino" flags
For Vista 64 you would choose the
MPICH version.
Whichever option you choose, if the GPU is going to share a core with another client you have to set the priority higher on the GPU configuration.
It's a good idea to install
fahmon or another monitoring program to keep an eye on PPD output, just to make sure everything is installed properly.
Check out
the official folding forums for more info.
Running vista with ATI your CPU usage should be relatively low for the GPU client. Realistically that leaves you two cores. Personally, I run SMP and the GPU with a AMD dual core. I love that I'm doing something that benefits science/humanity, but I'm in it for the points (also a reflection of how much work you are doing). SMP + GPU will result in the most points.
Let me know if you need any more help.