Combine the two!
Yesterday, after work, I hitched my backpack onto my shoulders and headed down the hill to my local grocery store. I only bought a few things--rye flour, pistachios, swiss cheese--so the load was not too heavy on the way back. The walk was over 4 3/4 miles of variable terrain, so my legs got to experience hills, stepping up and down curbs, stopping and starting at traffic corners. In addition, my brain got to experience some new scenery, and trying to remember the residential street map so I could avoid the high-traffic streets. As an interesting bonus to this all, I got to enjoy a little music to see me on the way home: the area high school marching band was giving a little concert outside the grocery store.
The only disadvantage was walking on pavement. I would step off onto dirt whenever I could. My feet are so much more energized walking on actual earth.
Since I didn't own a car until I was in graduate school, for all of college I walked around to whatever shops I needed to visit. Sometimes the load in my backpack was excessive--especially since it was filled with more canned goods than fresh foods. However, even now that I can transport myself quickly and easily in my car, it makes sense sometimes to just walk, or ride my bike. After all, I like to exercise, and I like to be efficient.
Once home, I cooked up and enjoyed a fabulous dinner: pesto mashed potatoes, leeks, peas, asparagus, salmon and a little pinot grigio. Plus a few crispy almonds for dessert.