I also use campus pedals on my commuter and love them. I have a second pair of cycling shoes that I wear when I'm commuting, or running errands and I know I'll be on and off the bike a lot. They're Shimano mountain bike shoes, and are flat on the bottom with rubber soles and recessed cleats so I have stable footing while walking around - I hate walking in my road shoes and slipping all over the place, as well as worrying about messing up my cleats. Might also try some spin shoes - for a mile commute, you wouldn't be putting too many miles on the shoes and be able to walk around in them, too. Just a thought