We'll respond shortly.
One client decided that Web 2.0-style rounded corners are only needed in Firefox and Webkit-based browsers because they are “free” with CSS properties built in for those rendering engines:
-webkit-border-radius. Internet Explorer is going to be left in the 1.0 world, at least for now, due to the over head of managing rounded corners.
Feel free to promote your personal favorite rounded corner techniques in the comments.