Here are my most frequently used shortcuts. These are for the Visual Studio 2008 C# development settings, so may not work using General or VB.Net settings.
Building and Debugging
F6 Build
ALT + D, P Attach to process
ALT + D, P, N Attach to NUnit (unless notepad is open, :-))
Text Editor
CTRL + X Remove current line and place it on the clipboard
ALT + SHIFT + T Swap the current line with the line below it
CTRL + K, C Comment
CTRL + K, U Uncomment
CTRL + M, M Toggle Outlines
CTRL + M, 0 Collapse to Definitions
IDE
CTRL + ALT + L Show the Solution Explorer
F4 Show the Properties window
ALT + SHIFT + ENTER Full Screen
ALT + W, L Close all the open documents
ALT + F4 Go Home for the Day
CTRL + SHIFT + A Add new file
Refactoring
F2 Rename
ALT + SHIFT + F10 Open "Smart Tag" menu - Great for adding "usings" without typing.
SHIFT + F12 Find all References
F12 Find Definition