@OP: The X31 will play audio from all those sources and, if you add the chat adapter cable to it, you'll be able to use the mic. Not sure about the wii.
It's an absolutely awesome headset. My buddy has one that I've used a lot and it's incredible. The simulated surround sound on it is so good...
I have a set of these and they sound incredible. I would really strongly suggest picking them up at that price, it's a steal. The Dolby Surround Sound is really nice on them, plenty of bass without it overwhelming the sound and they have given me a big edge. Love them on movies from the BluRay...
Definitely do NOT buy something from the shack. The TB talkback cable has microphone control on it, it's not "just a 2.5 to 2.5 cable." Email them at [email protected] and they'll probably just send you a new one for free lol