Walking is one of my two primary forms of exercise, the other being various dance related things (e.g. zumba). For those who like to walk and who travel frequently, I highly recommend Volksmarch. This is an international program, with (usually) 10K non-competitive walks in various places at various levels of difficulty. Some events ("regular" events) are just one day (or one weekend) while there are also "year round" or "seasonal" events that can be done any time. You get awards (pins and patches) for the number of events you do and distances and there are also various special programs you can sign up for that cover events passing particular types of landmarks (e.g. I've done rivers, railroads, historic churches, museums, American Cities A-Z, etc.)
The costs are reasonable ($5 for the event and distance tracking books, $10 for special program books, $3 per event for credit) and it is a great way to find walking routes in other cities. If you're slightly obsessive, it can also provide great excuses to travel. For example, I recently went to San Antonio for a weekend, primarily because one of the walks there has consistently been rated one of the best in the U.S. (I did a second walk there, as well.)
For more info, see
www.ava.org
But, yeah, I walk around my neighborhood, too. Particularly since there is a large park with nice walking trails just a couple of blocks away. Sometimes, in good weather, I walk part of the way home from work.