I have Visual Studio 2010 /SP1 / MVC 3 (With April Tools Update) installed on a machine with a fresh install of Windows 7 64-bit Professional.
I do not have resharp
I had this problem with one of my projects and the problem was the project somehow got converted to a Class Library project when I converted it from a standalone MVC app into an Orchard module.
Fixed by opening the .csproj file in a text editor and replacing this line:
<ProjectTypeGuids>{fae04ec0-301f-11d3-bf4b-00c04f79efbc}</ProjectTypeGuids>
with this:
<ProjectTypeGuids>{349c5851-65df-11da-9384-00065b846f21};{fae04ec0-301f-11d3-bf4b-00c04f79efbc}</ProjectTypeGuids>
I fixed it by right clicking on the cshtml file and selecting "View Markup".
You probably have already tried that one, but for me the steps in this blog-post worked: http://blogs.msdn.com/b/webdevtools/archive/2011/03/24/razor-tooling-for-mvc3-rc-with-visual-studio-2010-sp1-rtm.aspx
Like BuildStarter mentionned, Click Open With and set the default to Razor Editor even if it's already set. Should get the color coding and intelisense.
Please note that for me what caused the problem was the Roslyn Language Services plugin installed. When I uninstalled the plugin the issue was solved. To uninstall the plugin simply go to tools->extension manager and find the plugin Roslyn Language Services. Click the uninstall button and restart VS2010.
Razor Intellisense work with Razor Editor
Check if it is selected as default editor, For this do
Again check files must be opened in Razor Editor. I have done this and its working now.