I use a Shimano MTB pedal on my road bike. The one I use has a platform on one side and a clip on the other. This way if I just want to tool around the neighborhood with my wife I don't have to get all dressed up.
Also I find it easier to walk around when I stop with a MTB shoe. I don't have to worry about slipping as much and I don't sound like a horse clip clopping down the street.