While randomly browsing tonight I found FoxyTunes, which basically puts a connection to your music player (looks like pretty much any platform) controls into the firefox window. I'm not sure how useful this is in Real Life yet, but so far it's handy to be able to just mouse down to a play/pause/next/prev button instead of hitting the key on the keyboard, or going to a separate app. Similar to the WMP windows toolbar thingy.
It's pretty nifty... I have it installed on my browser at work.
FoxyTunes is an Extension for Mozilla Firefox.
It also supports the Mozilla Suite and Mozilla Thunderbird. It allows you to control your favorite media player without leaving the browser. The controls are positioned on the status bar or one of the toolbars, so no extra space is wasted.