For some reason or another (well possibly due to uninstalling R#) intellisense had stopped working in Visual Studio (2005).
It's fairly easy to rest it. To do so enter the following commands into the console from the \progra files\Microsoft Visual Studio 8\Common7\IDE directory:
1) devenv /setup
2) devenv /resetuserdata
3) devenv /resetsettings CSharp
Restart VS after step 3 just in case.
This will clobber any customised settings such as fonts or colors you may have installed. For me it killed the TextMate theme I had installed. Worth it to have intellisense back!