For me, I have stopped buying new soundcard after I got my first external DAC a couple of years ago. I was using an EMU 1212m before and at that time, people were saying it was one of the best cards for music but the external DAC just sounded so much better in every way. I know external DACs cost a lot more and you get no special sound effects for games, but this is perfectly fine for me as I would rather pay more and sacrifice some gaming effects for better music quality.
As for lossless vs 320Kbps MP3, I can only tell the difference between the two only on certain well recorded songs even with my Omega 2. The easiest place for me to tell was the very low frequency part where the bass has more weight in the wav files. The difference was definitely subtle though. I surely wouldn't notice the difference if I weren't listening carefully.
Good post thanks.