I love walking as well! One thing it does do for you that cycling doesn't is provide a weight-bearing method of exercise, which is great for your bones.

My workplace just moved to within 3 miles of my house, so lately I've been fond of the walk to and from work. We'll see how that goes, though the winter, however. I may shy away from the darkness, and choose to cycle-commute and shorten the trip by 25 minutes.