Pro and Ultimate have absolutely no advantage for normal users. http://windows.microsoft.com/en-US/w...oducts/compare
Also the memory limit is different http://msdn.microsoft.com/en-us/libr...mits_windows_7
And about the soundcard: If you like good sound and don't have a soundsystem with digital input you should buy something like a Asus Xonar D1. Onboard sound always has issues since the raw audio outputs are being hit with interferences by the surrounding mass of chips and lanes.