I agree that education is key, and Nole's upbringing is exactly what I always suggest, i.e. allowing supervised handling and shooting of the gun, taking away the mystery of it.
There will always be the trade-off between secure storage and quick accessibility. At my house, my youngest is 17, so Marlin and I have no problem with keeping a loaded pistol in each bedside drawer. With small children, obviously, this would not be an option.
As far as locking goes, there are several different ways to lock a shotgun, from trigger locks to cable locks to bicycle-type locks.
There are also "collars" that can be mounted on the wall (usually inside a closet) to lock the gun. The Loc Box is one example: http://www.mossberg.com/locbox.htm
Another is Tuffy's Gun Collar http://www.tuffysguncollar.com/TGC_How.html