only IE6 or IE7 works with a lot of sites
My friend and i tried "unsuccessfully to upgrade to IE8 from IE7" and lo and behold .. all our banking related sites stopped working .. the IT guys at the banks said - we had to use only IE6 or IE7 .. sorry no support for IE8.. this seems to be a problem with a lot of websites - esp those where you need to get your work done - eg. Government web sites, Banking sites etc.. they seem to just dislike any other browser except IE6 or 7. These include banking majors like HSBC, Standard Chartered etc just to name a few ..
of course as Gordon rightly points out .. coding practices, then prevailing MS policy regarding IE and the general apathy and ignorance of the mass public to knowledge regarding safety / security measures when using the Internet or a browser .. all lead to being stuck with an older version of the browser... hopefully Windows 7 will not enforce IE8 as the default and will allow people to "downgrade" to IE6 or IE7 .. otherwise it will be an useless OS for people whose work programs / intranets etc work only with those archaic unsafe browsers.. It'll be interesting to see how MS tackles a problem they were also partly responsible for creating in the first place ..