If you've only got one bike (which we can't condone), having clipless pedals doesn't make much sense. Especially when you want to make a quick run to the store without starting up your automobile. We've got a solution. Well, Shimano has the solution, but we'll sell it to you.
The Shimano PD-M324 Pedals accept SPD mountain-style cleats on one side for your multi-hour hammer rides, while the other side is a standard platform for safe pedaling while wearing any shoe. The M343 pedals come with cleats and adjustable tension.