Is there a button or shortcut to reset GE to vertical and facing North?
Google Earth Explorer
Not sure that a shortcut exist of that, but there is 2 shortcuts you might find useful:
n Reset your view to north
u Reset your tilt/angle to top-down view
+ - zooms in out
arrows move left right etc..
By the way, I found a good page for all of these that pointed out that there is in fact a single key to return you to north-pointing and looking straight down. That key is 'r'. (for 'Reset view' perhaps)
This is the Google guide that lists all of these.