I don't need anything more than The GIMP(I do use it, I do better things than my Winamp icons). Version 1.3(beta) is really good, but unfortunatly it doesn't work well if you get the prebuilt binaries installer for Windows.
If you do get The GIMP, please use indexed images in a compressed format when you put things onto the web. It will save dial-up users alot of time.