organize my mp3s

This is going to take a long time, since I have over 15,000 songs. But the main thing I need to do is clean up the dead files, and tag some things correctly. Most of the songs are correctly tagged, since I tag them as they come in, and the folders are organized (which is about the only thing iTunes is good for). I also need to get rid of stuff I know I will never listen to and clear some space on my external hard drive.