whether mp3 mixing is good or bad, I dont really care, but it is fun... I definately recommend http://www.carrotinnovations.com its got all the features and you can do it with 1 sound card and still have a headphone preview if you have a stereo splitter...
Christian you'll be disgusted to know i've enjoyed mixing your tracks as mp3s on many an occasion :) ScottV. http://www.mp3.com/ScottVallance