The CSS box model is something that has always tripped me up. I've read a bunch about it, but I never found a nice, concise, easy-to-follow explaination of the problem AND SOLUTIONS. I'm sure they're out there -- I just haven't found them.
Yesterday there was a fantastic article posted at 456 Berea St. outlining just that. The explaining is very clear, and more importantly, possible solutions are laid out in an easy to understand fashion.
Armed with this new understanding, I started using the information in a project right away... I really like their preffered method...
1. Avoid situations that cause problems
This is how I prefer to solve the problem. I simply avoid specifying both width and padding or border for the same element. This ensures that all browsers will use the same total width, no matter which box model they use.
Simple, clear, and effective.
Check it out: Internet Explorer and the CSS box model...