I am interested in the following features: Code highlighting, Intellisense, Refactorings, Code navigation (Go to Definition etc.).
If this functionality is missing from Visual Studio 2010 maybe Microsoft is planning to add these features in the future or there are community project to develop IronRuby tooling add-in?
Microsoft has recently released IronPython tools for Visual Studio and they are working on the same thing for IronRuby. No planned release date yet but they are working on it.