Walking is one of the best forms of excersize.  In addition
to being good for the body it, it is also good for your
state of mind.  While you're out walking, you get to 
meet the people in your neighborhood, smell and
breathe the fresh air, and look at the trees, buildings,
and yards.  This will help you lose the stress
and get into a more peaceful frame of mind.

Walking has environmental impact too.  If your walking
to do your errands, then you are not driving there.  This
means you are not burning fossil feuls and your won't
be contributing to the green house effect.

Walking is fun and good.