What's the loss in fidelity in the process? I've heard mp3's are terribly compressed compared to CD's, which themselves were cutting corners from analog recordings.
You can always do lossless encoding from a CD if you're a purist, but the storage requirements are much greater, though anymore that's not much of an issue on computers... still something of an issue on portable players, but not as much as the fact that a lot of portable players don't support any lossless codecs (or only support their own kind, ahem ipodphone)
mp3 is kind of out of date anymore. AAC is a much better choice, though it's still lossy. I think the common wisdom is that 128-160kbps AAC is comparable in quality to 320kbps mp3 (which as far as I know is the highest officially specced rate you can use with mp3)