Hi! I've recently bought a MBP 17" and I have a few questions to make sure I won't buy something just to find it won't work on a mac. At home I've got a 7.1 sound system from creative, so my first question is whether I can buy an external soundcard from wherever to make my mac able to play 7.1 sound? Secondly, are there external numeric keypads available for mac? I ask these questions because everywhere I see "Requirements: Windows". Is that how it is, or will some of these devices work on a mac anyways? Thanks in advance!