I've eaten at many a bagel shop, and, indeed, several of Finagle A Bagel's various locations. The one right by Park Street stands out in my mind as one of the best. Why? Because the employees are friendly, it's steps from the T, and they never run out of salt bagels unlike some other Finagle locations (I'm looking at you, Harvard Square!). My go to snack is a salt bagel with veggie cream cheese, although their bagel sandwiches are really tasty, too. It's a great alternative to the fast food joints that litter the Park Street/ Downtown Crossing area!
Pros: Tasty, inexpensive snacks
Cons: Carbs (wah, wah)