I highly recommend trekking poles. While they can be pricey, they add shock absorption to protect your knees and ankles, plus they increase calories burned, while seemingly easing the exertion. Also, hiking with them in slience can be quite a meditative experience.
I've been seeing plenty of people with trekking poles on hikes, and was considering getting one myself. I imagine it helped ease the pressure on the body, but I didn't know too much about them. Now I'm definitely going to head to the store to get them.
I must ask, though, how do you figure it helps increase the calories burned?