I've been using this greasemonkey script for a while now and I love it (I love it so much that its the only thing keeping Google Chrome from becoming my default browser). It's called StackOverflow 2.0 and basically what it does is round the corners of certain objects, as well as a few other CSS tweaks, on the SO family of sites (see image below).
So I was just wondering if Jeff & company have ever thought about incorporating some of these features? Right now the only thing that I can see that is holding the script back is the use of the Firefox only
-moz-border-radius property (however a few browsers now support the CSS3