Daniel Luz of http://mernen.com/ says:
For “Things You Can’t Do In IE6″, I’d like to suggest an article about min/max-width. I find it to be a quite useful feature, and IE7 already supports it, so it could be another nice argument. -Daniel Luz
These four CSS properties (min-width, min-height, max-width, max-height) do pretty much what you expect (in modern browsers): set an element’s minimum and maximum width and height).