I think the X-Fi is a great sounding card, so I have one in my carpc. If I knew how much of a headache it would be dealing with the Creative drivers, I probably would've gone with a different solution. I have a Platinum in my home PC, works great. XtremeGamer in my carpc, hours of frustration. But it works right now so I'm happy.
Use AC3Filter to convert 5.1 audio tracks to 4.1. Works great.