Since I do a lot of listening at my computer with my Sony cans, I'd like to get a parametric EQ program or plugin to really make the most of their sound.  Every media player has a graphic EQ, but I have yet to find one with a decent parametric EQ where I can set multiple bands.  Any ideas?  It can be a plugin for a media player, or a standalone program. 
Oh, and free is gooooood.