I just bought the logitech z5500 and my question is, how do I set them up to get the best sound quality for pc,xbox 360,ps3 and normal cable TV viewing on a samsung lnt 4681f? What cables will I need to buy? do I need a high end sound card? or would everything be better off connected to a good reciever with these speakers? I'll be mostly playing games and watching TV/dvd's.