I just got a similar device (well, not 5.1) but Plantronics digital headphones/microphone combo via USB.
One cable is nice. Sound is about as good as you'd expect ear pieces (i.e. not great), but it does a remarkable job with the surround! WOA! BF1942 got a whole new facelift! Or soundlift...?
Anyway, I used to use a 4.1 setup (via S/PDIF) but my kids kept screwing up the rear speakers so that became a 2.1 setup... lost the surround and forgot how cool it is.
Plantronics ($50 later) to the rescue. The mic is fine, and I actually wanted a mic/headset combo (for voice dictation goofing around). But now I'm thinking of teamspeak, etc... possibilities.
Anyway, back to this Philips deal: anything that REDUCES WIRES is a GOOD THING! Period.