Smashing Magazine has posted a great article on CSS support between the different versions of IE.

The article is very in depth (I learned some new CSS Properties) and well worth a read. The only noticeable ommission I found was the IE6 double margin bug which catches me out on a regular basis. 

You can read the article here: http://www.smashingmagazine.com/2009/10/14/css-differences-in-internet-explorer-6-7-and-8/