Dan Rubin: The final word on IE6
One of the benefits of web standards is that our documents are marked up correctly before we reach the presentational stage. One of the benefits of IE6 (et al) is that we can target specific versions using Conditional Comments. The combination of the two means we can still send our content to old browsers, but not have to bother with the presentation, thus saving ourselves hours of needless headaches and frustrations, while not punishing the users of said old browsers by denying them access to our content. (via)