Harpoon IPA. I've had a couple chocolate stouts previously (Sam Adams' Chocolate Bock and Young's Double Chocolate Stout) and this is certainly my favorite.
It pours intensely black with a good three fingers-worth creamy, light tan head. Retention and lacing are great. The aroma is unmistakably chocolate, particularly dark chocolate, with perhaps a hint of roasted malt. Absolutely awesome!
Like most other type of dark beers, I find that the various flavors present in a chocolate beer present themselves better as the temperature of the beer increases toward room temperature. I drank Harpoon Chocolate Stout straight from the refrigerator and it was amazing. This beer is all about chocolate. On the front end you get a rich, sweet, almost milk chocolate taste. On the finish there is bit of bitterness akin to bar of dark chocolate. I also detected a faint hint of coffee. Mouthfeel was very creamy with average carbonation.
I really hope this beer is available in a the 6-pack variety next holiday season because it is absolutely worth purchasing again. Other "chocolate" beers I've tried had tastes that were reminiscent of chocolate, but I found the flavor to be underwhelming. Harpoon Chocolate Stout is exactly what it says it is, and it is a pleasure to drink.