Mount Monadnock is one of my favorite local hikes. It is just over 3,000 ft tall, but the top is completely bald and you get 360 degree views from the summit.
The Marlboro Trail is a great way to experience the mountain. It is located off of Shaker Farm Road in Marlborough NH beginning at a small parking area. The trail itself has some really steep sections and at points you have to scramble up using your hands and feet, but you are rewarded with some great views on the way to the summit.