Sara Ford covers lots of lovely tips: http://blogs.msdn.com/saraford/archive/tags/Visual+Studio+2008+Tip+of+the+Day/default.aspx
But some of my favourites are Code Snippets, Ctrl + . to add a using
<Namespace> or generate a method stub.
I can't live without that.
Check out a great list in the Visual Studio 2008 C# Keybinding poster: http://www.microsoft.com/downloadS/details.aspx?familyid=E5F902A8-5BB5-4CC6-907E-472809749973&displaylang=en