CSS rule for XP/SP2 only?
I've found a layout inconsistency in a page I designed that is definitely caused by rendering differences between IE6 (6.0.2600 or 6.0.2800) and IE6 on a WinXP w/SP2 machine (6.0.2900).
You can look for "SV1" in the user-agent string and send down different CSS based on that. A little more info:
A server-side solution isn't the most elegant way of dealing with something like this, but then again a CSS hack probably wouldn't be either.