Open Source CSS Helper Library - What features would you like to see included?

I plan on releasing a library of JS functions designed to provide functionality for CSS properties that Internet Explorer does not support. It will work in conjunction with the IE-only expression operator. This will be an open source effort, so it will be free to use, but it will adhere to the strict standards of quality I follow in my professional work.

I intend to do the usual min-width, max-width, min-height, max-height, etc. Which CSS properties would you like to see support for? Let me know, and I'll do my best to include them.