I found this on Apple's downloads site today. It's an application called Hear, that looks like it is a stand alone system-wide equalizer/surround simulator/lots of other audio adjustments for the OS X.
Sometimes I use iTunes for playing music in the car, and I have some pretty nice EQ presets in that, but when I go back to AMP, I can definitely notice the difference. Hopefully this will take care of that.
Does anyone know any more about this, or have any experience with it?
http://www.apple.com/downloads/macosx/audio/hear.html