I've really like Internet Explorer 8. But there are still lots of sites that don't behave well, requiring the use of compatibility mode. That's easy enough for us IT guys, but end users don't necessarily figure that out. And the sites aren't going to be fixed up fast enough to suit everyone. So the IE team is going to do more to help by offering a website list built from community feedback, downloaded through Windows Update. (I like to think of it as "IE shims" for those who are familiar with the ACT terminology.) See Scott Dicken's post on the IE blog at http://blogs.msdn.com/ie/archive/2008/12/03/compatibility-view-improvements-to-come-in-ie8.aspx for more details.
(For those of you who have been active in deployment for a while, you may have crossed paths with Scott before: He was formerly the program manager for Windows Deployment Services, but has been with the IE team for a while now.)