It's a nifty tweak, but for my personal computer I don't see the point. I see the logon screen for maybe 3 seconds each time I log onto the computer. I can see it being useful for OEM's or resellers to advertise their business or people that just have to tweak everything and make their OS "their own."

Would be nice if Microsoft made it as easy to set the logon screen background (almost) as easily as the desktop background.