Commercial product (Windows): UltraEdit.
Freeware (Windows): Notepad++, PSPad.
Cross-Platform: JEdit. It's written in Java and runs on almost anything.
If you don't mind taking a performance hit under Windows, JEdit has some amazing capabilities. For native performance on that platform, I would go with one of the others. I tend to switch back and forth between Notepad++ and PSPad. Notepad++ probably edges it out for most tasks. It has section folding, which is very handy. However, you did ask about products other than that one.