Hi
In general I'd say that MSIE should be avoided and updated to newer version like 7 or 8 (according to wikipedia they should be avaible for Windows XP - or at least they were available when Windows XP was supported) - IE6 have technology from 2001. I understand however that it may be outside your control (maybe portable Fx would be solution?)
I strongly agree that MSIE 6 should be avoided, but for many company networks it's required. The big problem isn't that 16% (or whatever) of people use it, it's that while technical people will use a modern and powerful browser, many non-technical managers will just use the default settings/systems, and it gives a bad impression if when told that "Haskell is a great tool" a manager looks up haskell.org and sees a messy splat. For reference, the new Haddock style also gives various rendering issues in IE6. I reported these a while back (to Mark) but never got any response. Thanks, Neil