Boston has to be the winner for Massachusetts. The state really has a lot of looks, with almost 200 miles of coastline (including the Cape and Islands), many lakes/rivers, industrial cities, charming towns, cookie cutter suburbs, and the mountains region to the West. Every other city or town, while culturally distinct from MOST of the state, still has a counterpart (or many) that can be found scattered in Mass. There is only 1 completely dominant city (including inner subway-connected suburbs), and it has more going on urban-wise than the rest of New England combined.
The even more interesting thing about Boston is that the neighborhoods themselves are also culturally distinct from each other. The haphazard layout, Charles River, harbor, and hilly terrain all contribute to the different feels as well.
The North End alone (see below) might be the most fascinating (remaining) neighborhood in the whole country. Looking up this thread, it's unbelievably painful to think of all the damage caused by urban renewal here and across the country (looking at you Pittsburgh!!!). Otherwise the North End would basically flow into the West End and from there into Beacon Hill, with Scollay Square (now Government Center/City Hall) bridging the gap back to downtown. The elevated highway (now Big Dig tunnel) also demolished many blocks of beautiful urbanity. It really is tragic that people in power did not see the value of this unrecoverable architecture and thriving density.
North End Boston Real Estate Aerial by
David Oppenheimer, on Flickr