Does the Live! X-Gamer (non 5.1) have a game/joystick port?
Does it have two channel audio input jacks? (I noted that the video capture card I just got for an el cheapo price courtesy of these parts, the Pinnacle DC10+, doesn't have any audio inputs.)
Re 4.1 channel vs. 5.1 channel, it seems to me that the latter is only useful if you plan to do a lot of watching of DVD's on your computer. If you watch them on your big screen tv with a separate DVD player (mine's the Apex), then I'm not sure of the point. The center channel isn't used much in games, if at all, and would tend to hurt the impression of sound direction. It's best for person to person closeup dialog in movies, tv shows, etc.