I have a 5.1 speaker system (creative inspire p580 if you want the exact name!) hooked up to my PC at the moment, and have been looking at ways of connecting this to an iMac which I plan to get in the next month or so. It's not got a digital in connection on the subwoofer so hooking it straight to the mac isn't an option. How reliable/practical are firewire or usb soundcards for macs, or am I better off upgrading my speakers (which I could do for between £80-£130 for a basic creative 5.1 with digital). Thanks in advance!