In the Fenway/Kenmore neighborhood of Boston is Sweet Cheeks Q, a barbecue joint from Top Chef finalist, Tiffani Faison. It's noted to be the most expensive bbq place in Boston, but possibly also the best.
You can order meats by the pound or get a tray with 1, 2, or 3 meats (the last one is called the Fat Cheeks Tray) that comes with two sides.
Above anything else, though, you have to - absolutely must - get the biscuits with honey butter.
If you're getting meat, then I would recommend the brisket.
The pork ribs were also quite good.
I didn't get to try these, but the fried chicken looked pretty good.
For the sides, I really enjoyed the carrot and raisin salad, while the mac and cheese were rather disappointing. Switch it up with collard greens or beans instead. I've tried the bbq from another Boston place, Blue Ribbon, and while the prices here are higher I'd have to say the brisket at Sweet Cheeks was much better and well worth the price difference! I can't reiterate enough, though, about those biscuits ...
Sweet Cheeks Q
1381 Boylston Street
Boston MA 02215