There is an article over at sitepoint on a rounded corner technique for DIV’s called Spanky Corners. The big upside is that it only requires a single div and the CSS takes care of the rest. Kinda neat and an interesting CSS puzzle if you are into stuff like that. I also liked their technique for generating the the rounded corner gifs. Very clever.
As a side note. This is also another example of why programmers are bad at HTML design. They leave it to the designers for figure out how all the CSS rules and exceptions (quirks) work.