Anyone know of a really fine-tuned equalizer for Windows?

After reading some of the stuff in this thread about tinnitus I decided to try the audio notching solution. I was going to go through my entire library and modify the files, but rather than have 12gb of duplicate music, I think I probably should just install an equalizer. So how ‘bout it? Anyone know of an equalizer that runs separate from iTunes/Songbird/what have you that can be really picky? As in, take out frequencies of exactly 10khz?