Earlier today, I got an email from a firm representing Waves (maker of audio signal processing technology) earlier today. What was refreshing was the fact that this was how the email started- they noted they had a product that might be of interest and were completely up-front about their relationship with their client.  Think what you want, but this was an interesting way to start a conversation IMO.

Here's a link to their latest release of MaxxPlayer. It purports to do volume normalization, bass and treble enhancement, and spatializing. I haven't had a chance to take a look yet, but will do so this weekend. In any event, they should list this on www.wmplugins.com too.