Batten down the hatches - we've got a new User Agent String
It always happens - a new version of Internet Explorer is released and some web sites break because they are *not* using best practice when detecting browser versions.
Internet Explorer 8 will introduce a new UAS, Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0), and I know that web sites are going to break. The most common problem encountered (in my experience) is the web site will erroneously report that you are using an old (unsupported) version of IE and prompt you to upgrade.
Please, consider using conditional comments if you must detect Internet Explorer version. Far too often web sites break, not because they will not display properly in IE7 or later and the web designer has made a conscious decision to address the problem by barring access to the latest browser version, but simply because the site does not recognise the latest UAS and serves content that is completely inappropriate. Ironically, every time I have encountered such a site, it displays just fine if I spoof the UAS.