I currently have a sb audigy card, and I was all set to get the m-audio 2496 until I stumbled upon the art dio. The art dio peaked my interest because I could use it with any source i have. Any suggestions/comments to help me decide are appreciated.
If you can do some DIY the consensus seems to be that the Art DI/O will outperform a lot of high quality (and expensive) DACs out there. I have not heard either but I think the DI/O would be better since it's more flexible. That is no excuse to stick with a crappy digital source though, you should upgrade your soundcard whether or not you get the DI/O. Have heard good things about the Acoustic Edge (Kelly uses this, perhaps he can chime in) and the Santa Cruz