After buying my Creative Nomad Zen Xtra I've learned more than ever that having all of the details filled in for all fields in the ID3 tags is a must. I have found in the past that going through Winamp to make changes to ID3 tags is far from ideal. For instance, if you want to fill in the Artist field for 15 tracks you'll end up typing it in 15 times or pasting it each time.
Does anyone have any good utilities for dealing with ID3 tagging for existing mp3s? Obviously for albums that I rip myself I do the tagging properly these days, but many in the past I was not as diligent with.