CSS can do stuff now that web designers have been wanting for years. Rounded corners can now be accomplished with a CSS spec instead of the horrible corner-GIF and all the kludge that goes with it. Here is a screenshot of a site I built that utilizes a rounded-corner design.
It is true that the rounded corners will not render in Internet Explorer, but for I would choose to sacrifice IE for the sake of clean code, as long as functionality is not affected. In Apple’s Safari browser even the images have rounded corners. The fact that other browsers do not render this doesn’t bother me: a little extra for some users is a fine thing.
CSS was also used to display the title of this site at an angle, using the rotate specification. The ability to tilt browser text is one of the most interesting things I’ve stumbled on recently. You can actually rotate almost anything, and break free of the everything-has-to-be-as-perfectly-level-as-a-computer-can-render-them paradigm. The fact that IE will display the title level is fine with me too. IE can be IE, I don’t mind.
The pale shadow around the edge of this window is also a CSS3 spec. Originally I had a much wider shadow, but I found that it slowed down the rendering time a lot, so I had to scale that back.