bobcat - HLaB is exactly right. I have a pair of Specialized shoes which are designed for MTB/Cross use, they have a rubber sole which is rigid but still offers a little flexibility, as well as the reflective strips HLaB mentioned. They are very easy to walk around in, and basically look like trainers when you're not on the bike. My other shoes are a road pair which have a completely rigid sole. Without the cleats they would be easier to walk around in, but probably not as easy as the other pair as they have a lip at the front of the sole to protect the cleat.
There are arguments to be made for increased rigidity and power transfer, but personally I don't buy into them. For comfort and practicality, I'd go for the MTB style.
HLaB - Being possibly, slightly, a wee bit ambitious, I skipped the toe clip stage and went clipless. I promptly fell off at the first set of traffic lights I came to, despite all my practice in the living room. There is no less dignified way to dismount a velocipede!