Anyone upgraded from audigy 2 to x-fi xtreme audio?

No there isn't. while the x-fi xtreme can handle gaming audio better I've found most games just don't make use of that many sound points. And in stereo sound there isn't any difference between onboard and dedicated cards anymore. I think a lot of people mistake the effects that the software equalizers that come with the hardware have as "improvement". But that's just me.

Don't waste your money. If you don't have a surround sound system then I wouldn't bother using the audigy 2 over the onboard.

I didn't notice any difference in 3d between a x-fi and a audigy 2. If your really unsure just pick one up locally and return it if you don't hear the difference like I did.