By any means, don't install IE6!It doesn't support Netscape-compatible plug-ins anymore, which means that you can only use ActiveX plugins. The more important ones like Shockwave, Flash, and Quicktime have been converted to ActiveX, but some less common plug-ins aren't.
And they've placed MSN everywhere. IE5 had it everywhere too, but IE6 is even able to surpass that.
Don't download it, it's just another try of Microsoft to take over the web.