Well, Google will find you plenty of benchmarks.

Don't worry about GPGPU, though, for now. You won't be able to write GPGPU code at least for a year or two after you start learning to program. By that time all those cards will be obsolete anyways.

The hardware is not really that important for programming. A P3 will do (assuming you don't want to wait those extra few seconds when compiling programs). Knowledge and experience are the hard things to get. Hardware is just money.