One important thing I forgot to mention is if you think you might own a portable
player in the future, use a format that it supports. Every player on the market
supports MP3, a good number of them support WMA, and only a few support AAC.
Ripping CDs as 192Kbps MP3s is the "safe bet". If you think you might only need
a flash-based player, then go with 128Kbps. There is a trade-off between
file-size and audio quality.