John, in your example you can't have div.buttons.hover. That doesn't work in IE6 unfortunately. I WISH it did. (http://commadot.com/?p=528)
I'm not sure how you're testing this, but it worked wonderfully for me (You even made me load up Parallels :-P). You need to be careful to make the order right, otherwise one selector may overwrite another, due to its order. --John