A couple quick ones...
Southeastern Massachusetts
Country Whip, Acushnet just after Route 105 turns toward Marion
This place is awesome. It's in the middle of a residential area out in the sticks, but it's worth the ride (and a cool ride it is, BTW). Great old-school burger stand food and awesome ice cream. My favorite is the Cowboy Burger, which is a half pound burger with American cheese, spicy BBQ sauce, bacon, and hand battered onion rings. It is a beast. They are also known for their seafood. A small ice cream is the size of a large at most places, and it's made locally, too. It's seasonal and closed for the winter.
No Problemo Taqueria, New Bedford (right in the downtown area)
Best burritos on the entire planet. Nothing can compare. Cheap, but cash only. They have a take-out counter as well as a regular restaurant area with a full bar. The only thing that this place could use is a recovery room that has cots so you can rest after housing one of their burritos. Seriously, time slows down after eating one. They also host free shows on Saturday nights, and lots of Stoner Metal bands have been playing there lately, like Elder, Magic Circle, and Pilgrim.
The Cabin, Middleboro (off of Exit 4 on 495, on Rt. 28)
Small place, and yes, it looks like a log cabin. Great seafood and really good pub-style pizzas. This one is right around the corner from my place. The pizzas are probably the best pub-sized ones I've had! Cheap eats too.
One more just south of Boston...
OB's Cafe, Quincy (on Billings Road, near Wollaston Beach)
My favorite breakfast place in the universe. Cheap and awesome, and they have great lunch too. They are cash only and only open until 3pm, but if you are in the area, it's a great spot. Order the Spuds and Scram (potato skins filled with scrambled eggs, bacon, and cheese, with toast, and more bacon, and home fries). It rules.