Portland! (The eastern one.)
Portland is big enough that there is a lot to do and see, but small enough that it retains its charm and grit. The downtown and Old Port neighborhoods are visually interesting: old cobblestone streets, tiny hole-in-the-wall pubs, pier after pier of fishing boats and lobster traps without much of the tourist-trap falsity that overtakes waterfront neighborhoods in many bigger cities.
Locals and friends recommended some good spots: Eventide for dinner of local oysters and brown butter lobster rolls, Top of the East for a drink overlooking the city, Brian Boru for a lively night of music, Collette for swoon-worthy handmade shopping and The Holy Donut for a lazy breakfast. As the sun set we walked around taking in the briny fog of salt water air engulfing Old Port while watching boats pull in and out, many lit for the holiday light festival.