This article is from the Bicycles FAQ, by Mike Iglesias with numerous contributions by others.
When it comes to cycling footware, I think the best option seems to be one of
the walkable clip-in shoe systems such as the Shimano SPD. Having a shoe that
you can walk in has two big benefits. First off, if you have never toured, you
will be surprised at the amount of off-the-bike walking that is done during the
course of the day in order to buy food, take photographs and check out historic
sights. Secondly, having to carry a pair of walking shoes means extra bulk and
I would not recommend Look cleats for touring. I do a lot of walking which is
unavoidable. It has been my experience that even a little bit of wear on the
Look cleat can make it behave differently in the pedal. While Look cleat cover
are available to protect the cleat during walking, during a normal day on the
road you do so much on and off the bike activity that it seemed like too much
bother to take the covers on and off and on and off, etc.