Do you see that Razor colorization, intellisense has stopped working after you have installed Visual Studio Sp1 RTM? The reason is that you might have MVC3 RC installed on the box which is not compatible with Visual Studio 2010 Sp1 RTM.
With the Sp1 release of Visual Studio 2010 now available for download, you now have the option to use IIS Express as the development server for your web projects instead of the built-in Visual Studio Development server (aka. Cassini). Here are some previous blog posts explaining the IIS Express integration features in VS 2010 Sp1 Beta,