go with the OEM, the software that comes with the retail is not worth the money. Plus, if you really watned those games you'd already own them, right? Some people will try to tell you that since the retail one has gold contacts that it is worth the money. However, the inside of the plugs is the same, I'm pretty sure... I think it is just a difference of how it looks on the outside. Plus, the colored jacks help to tell them apart. 🙂
FYI: you can order the retail Audigy X-Gamer or MP3 version from Staples.com, PM it somewhere else and then use a coupon to get the price lower than the OEM anyway. Do it this way and you can spend less money and get the retail version too!
Epsil0n