What happens when you export your iTunes library to an XML file, then try and open it in Internet Explorer 7?
This:
It took me a while to regain control of my machine and kill it. I’ve got 2Gb RAM anyway, but when you consider a normal session for me is using about half that anyway (not Vista’s fault, more the junk I run), it was swapping out to disk like crazy. The end result being lots of swapping, and a PC which is barely useable. The XML file is about 12Mb, but obviously all the other stuff in the default XML stylesheet in IE adds a massive overhead.
I shan’t be doing that again in a hurry.