After "Go to Definition", is there a command to return to where you came from?

You can go to the last place you navigated to by doing CTRL+-

(That's the control key and the "minus" or "dash" key.)

The correct way to navigate this stack is with View.ForwardBrowseContext and View.PopBrowseContext commands. In the default C# schema they are bound to Ctrl+Shift+7 and Ctrl+Shift+8 respectively.

Tip by Brian Sullivan (Ctrl+-) works great.

You also can use a side button on your mouse (if your mouse has a side button and that button programmed for Back functionality in a browser).

If you have an MS mouse with the latest Intellipoint drivers installed, you can have program-specific commands associated with mouse buttons. Find out what the "Back" keyboard command is for your program. For VS .NET 2003/2005/2008 it is Ctrl+\ (control backslash) which is tied to View.NavigateBackward. Then go into the Control Panel for the mouse, click on the checkbox for "Enable program-specific settings" and then click on Settings.

Click on "Add" and pick your favorite Visual Studio and map Ctrl-\ to the left button.

Others programs of interest:

uVision3 IDE (the Keil compiler):    Alt-Left
Adobe Reader 9.0:                    Alt-Left
javaw (as in Eclipse):               Ctrl-F2
VB6:                                 Ctrl-Shift-F2

Actually, the Eclipse one isn't Ctrl-F2 but is something that cannot be mapped, so I added that mapping within Eclipse and then the new mapping in the mouse driver.

Hope that helps!

In Microsoft Dev Studio it was always mapped to CTRL+* (The * on the numerical keypad) but not in C# Express, I notice. Here it's Ctrl+Shift+8, as already noted.