L.A. Burdick Chocolate Shop & Cafe in Walpole, NH has the most heavenly hot chocolate I've had to date (and chocolate is not something I consider lightly). It's a sign of my disease that I am even thinking about hot chocolate during a heat wave.
Walpole is located near the Vermont border so it's a hike from most places. The trip is definitely worth taking if you:
a) dine at their incredible restaurant while you're there
(check out their menu)
b) need a unique gift for a chocolate lover
c) are a chocolate lover yourself who just deserves it
If you have time to (and let's face it, you probably do since you drove all the way out to Walpole for chocolate), the town is beautiful and worth taking a stroll through. There's a beautiful park and gazebo right around the corner that, if you ask me, just begs for a picnic.
L.A. Burdick does have two other stores, one in Cambridge, MA and the other in New York City. Though lacking the old town New Hampshire setting, I'm confident the chocolate there will not disappoint.