Tremont Scoops is pretty good. They have a good selection of flavors, and also serve non-dairy Tofutti (although that costs more). Ice cream is priced by the ounce, not by size, which is cool, but having a set price wouldn't dissuade me from getting ice cream anyway.
They have ice-cream-cookie sandwiches, chocolate-covered bananas, and other freezer stuff too.
They are open "late" (10 pm) in the summer, though sometimes I've gotten there at 10 minutes to 10 and they've already shut the lights off...okay, guess I'll go get a pint of Ben and Jerry's across the street at Professor Market.
I think that the servers are generally blase and lacking in any personality. They're not exactly rude, just...unfriendly. Isn't part of the appeal of an ice-cream parlor to "escape" into a sweet-smelling world of happiness and dreams?
Ok, I'm a weirdo.