Don't like to switch between the keyboard and your mouse when developing in Visual Studio? This sheet is well worth printing for reference.

A few weeks ago Peter Himschoot showed a keyboard shortcut I had never used before: CTRL + . (dot) at an MSDN Evening event. This will show the SmartTag options for the element. In the case you are referring to a class for which the "using " statement has not yet been inserted it allows you to quickly select the required one with the keyboard.

Screenshot

This inserts the statement at the top of the class so you can continue on typing.
I've been using it heavily since. Learning about this easy shortcut made me look into the full reference sheet.