We got this keyless door lock and just love it. Granted, it was kinda a pain in the ass for Andy to install, basically because our door is old and had an old hardware setup. This would probably install very easily in a newer door with newer hardware.
But we just love that all you have to do when you leave is press 1 button (the lock button). And when you return you just need to enter in your combination number and the unlock button. No fussing with keys! And if you are in the car and realize you forgot something, you don't have to turn off the car. No accidentally locking yourself out......and when we are gone we can easily instruct the neighbord how to get in the house to make sure the cats have food. Very cool.