This is a really nasty bug as it affects us heavily on Stack Overflow with <pre> code blocks, which have max-height:600 and width:auto.
It is logged as a bug in the final version of IE8 with no fix.
http://connect.microsoft.com/IE/feedback/ViewFeedback.aspx?FeedbackID=408759
There is a really, really hacky CSS workaround:
http://my.opera.com/dbloom/blog/2009/03/11/css-hack-for-ie8-standards-mode
/*
SUPER nasty IE8 hack to deal with this bug
*/
pre
{
max-height: none\9
}
and of course conditional CSS as others have mentioned, but I dislike that because it means you’re serving up extra HTML cruft in every page request.