I get the best quality when I record direct to CD with vocals and all in one stereo pass. (I don't evenm use a mixer)
Then I use Pyro to convert to MP3 or WMA for use on the pc. Fast, easy and sounds great.
There are other ways to convert (some freebees too)but I like the way Pyro is laid out, and it's under $40.
This way I always have my original in a CD format too. Makes for a good archive media, and you can listen anywhere.