Today, after installing the RTM version of VS.NET 2005, I got some errors due to previous installs of the Betas. One of the was a Package Load Failure for the Class Designer. After a quick search on MSDN Product Feedback Center I found a case (FDBK39168, now closed) with a really nice tool that scans and fixes a number of known issues in Visual Studio.NET. You can download it here: http://astebner.sts.winisp.net/Tools/ttool.zip if you have the same or similar errors.
A really nice feature when using .NET Framework 2.0 (beta) is that you can run ASP.NET 1.1 nad ASP.NET 2.0 side by side on the same IIS. You can configure individual virtual directories in the IIS to use different version. The IIS Management Console has a new tab called ASP.NET, see image below, in which you can select which version you would like to use, whithout doing a lot of script-mappings.
This makes it really easy to make new applications take usage of the new .NET Framework while your old applications still use the .NET 1.1.