Just returned from a week in Bar Harbor/Acadia. We loved the Morning Glory bakery-everything we had there was outstanding. They might make the best croissants I've had outside France. They also make interesting sandwiches to pack along on hikes.
Other places we tried and liked:
Cafe this way
Trenton Bridge Lobster Pound
Lompock brew pub
Sadly the Bagel Factory is no more. There was a tapas restaurant where it used to be (we were just there last Sept.- don't know what happened.)