In the “Update Enhancement List” for Revit 2010 you may notice the “Application frame size is saved between sessions” note.
There is one additional item along with this for dual-display systems. Some users have requested that when Revit 2010 is dragged to a secondary display after launching the product it would remember that location.
After applying the update this is now the case. Revit will not only remember the application window size, but it will revert to the physical location if it was dragged to a second monitor as well. Previously it would launch within the primary display when the user first launched the application.