I just noticed that mp3Tag 2.35P was listed in the download section, and wanted to say that I use it and am very satisfied with it. It was the first tag editing program I ever tried, and aside from one part that took me a little longer to learn, I've found it to be an excellent freeware program that is very well supported/updated by its author.

The part that took me a while to figure out was how to script the proper syntax used to create the order in the naming I wanted. For example:
%artist% - %track% - %title%
There are a minimum of preset options, and if you want others you have to write them yourself, and that's what took me a while to figure out. But I've used the program to rename and organize thousands of my mp3s.