I also have the Auzentech (the 5.1 version) using optical out to my AVR. I think it sounds really nice-although I tend to prefer plain old 2ch stereo when listening to music. I think that's just me. You definately don't *need* an external CD Player if you have this setup. Personally I wouldn't really even want one. Playing CDs isn't rocket science, I find it hard to believe that there would be a big difference in fidelity between a sony discman plugged into your AVR via 9mm to RCA and a $2k CD Player. Your computer will likely play whatever format you'd want to play-so long as your computer's fans aren't very loud you'll be happy. I'd strongly advise against getting a standalone player just to have access to DVD-A or SACD. DVD-A never really caught on and SACD you can just play through Windows Media Player.
If you want to invest 350 bucks in getting better sound quality consider getting bass traps for the front corners of your room and a couple of acoustic panels for the first reflection points in the room. I recently treated my room and it made a huge difference.
If your heart is set on a separate CD Player, just get a separate DVD player that happens to play CDs.