I'm having the same problem and have posted a reply on the official ASP.NET MVC forum at http://forums.asp.net/t/1378448.aspx
I'm not sure, but are you also seeing reference to the Html helpers not showing up in the views (when they don't crash)?
I don't have Gallio installed, but I do have Resharper. I'll see if disabling that helps (although that would cause me a lot of anguish).
Update: Resharper wasn't the issue, but rather the plugin "Huagati DBML/EDMX Tools." It seems some plugins might be conflicting and I encourage people to disable all plugins as a preliminary step in debugging the crashes.