I spend alot of my time each day in front of a computer, or in class...
I'm finding walking is very good for minding my posture. Especially when I am carrying things. Somehow, when you're walking for more than a block it gets really easy to feel if your neck is leaning to far forward... or if you're not using your stomach muscles and back muscles in concert to keep your spine straight.
And if you've got a grocery bag (or one in each arm) it's alot easier to focus on how your spine sits on your hips... It becomes so easy to tell if the weight of the bags is more on your back or more on your stomach.
Also, Looking around is great! My eyes can get unused to focusing at distance and looking all around after long days indoors. It's a good eye work out to look out to the horizon, and up at the eaves of buildings and see architectural details, or around peoples yards and to see their flowers.
And of course, both ways before your cross the street!
Walking is good for....
I'm a computer programmer, and I used to get really uncomfortable sitting in front of the computer all day. But my habit of "lunch walking" has done wonders for that -- especially since I've added seven flights of stairs. Really gets the blood flowing. And it's a much better, more wholesome and satisfying distraction than checking my stocks, or the nytimes website, or slashdot (or this bulletin board 
).
Reinhard
).Reinhard