For Brent...

gistfile1.txt

tell application "System Events"
	
	set frontProcess to first process whose frontmost is true
	
	-- When it's down to just Finder and the front process, we have to switch 
	-- to the Finder first to get the front process to hide itself. Furthermore,
	-- the Finder will not be listed as among the visible processes unless it
	-- has open windows, so treat a condition of 2 *or fewer* visible apps as 
	-- meaning the Finder should be activated before hiding the front process.

	if (count of (processes whose visible is true)) is less than or equal to 2 then
		tell application "Finder" to activate
	end if
	
	set visible of frontProcess to false
	
end tell