To be honest with you I am not much of an Audiophile, I have always been fine with the onboard audio.
Big Bang gaming motherboard features Quantum Wave™ audio processing, combing THX TruStudio PC with Creative EAX® ADVANCED HD™ 5.0 to deliver the most powerful and realistic gaming audio performance available from any motherboard.
Featuring THX TruStudio PC created by THX, Quantum Wave™ can deliver the fullest audio experience for games, music and movies while remaining true to the source and intention of the artists who created it.
EAX® stands for Environmental Audio eXtensions and is a programming interface that allows developers to access the special features of Sound Blaster® cards. Compared to the previous generations, the latest EAX 5.0 allows users to have more realistic and incredibly immersive audio to games!
From the MSI Big Bang XPower page from MSI's site, it looks like it has alot of potential. I am looking at ways to test sound cards now, I will be setting up the XPower board again later this evening, and I will let you know if I find a good way to test audio quality.