Sorry for shameless plug. Was looking for a simple way of editing MP3 files (cropping, cutting, normalising, etc. without having to go to WAV and re-encode again; came across this:
mp3DirectCut

It's freeware and elegantly simple. Note it's not a tag-editor (well, some basic facilities for ID3V1). Thought I'd share this, if you know of something better still (and free), I'd love to know!