if you plan on playing games, keep looking for a sound card. the creative cards don't support realtime 5.1/7.1 over a digital output, i.e. S/PDIF. i bought a home theater system for use specifically with my pc, so i bought an auzentech x-plosion cinema card. it supports dolby digital live and DTS connect, so as a result it will output 5.1 sound from games to my reciever.
Yes they do - at least the Titaniums do, which is the one that is linked above. The older ones don't. I have one (specifically a Titanium Fatal1ty Pro) - you just have to enable Dolby Digital Live or DTS connect. It works great - I have mine hooked up to a Denon 2808 reciever.