You dont need a soundcard really, its really just for pretentious audiophiles, and if you are going to get vista like the pr0s, it causes more problems.You can still have decent 7.1 (usually 5.1 for most people) sound from your mobos onboard, and in fact the integrated ones are getting better. I would leave the soundcard for a later date.

Also Quadcores require very little energy compared to any AMDs