Boston. Where one campus ends, another begins. (Actually, you could say that about the entire state of Massachusetts.)
I guess in order to be called a “college town” the college(s) need to be over 50% of the local economy. IMO, by popularity, you cannot be beat the town called “Stanford, Ca” for the title.
Heampstead, NY! (Just kidding)
Williamstown, MA (for real)
Stanford? There’s no there there.
I’m always surprised our town seems to get no benefit from the colleges located there. I think it’s hard when you are within commuting distance to NYC.
Lexington VA (with Washington and Lee and the Virginia Military Institute) is a cute college town. At least when my parents lived there it had some okay restaurants, a nice bookstore and some funky art galleries. It’s also got nice walking and riding trails in the area. For my parents - the college professors meant there were some intellectual activities in the way of lectures that would probably not have existed in a town without a college.
Big schools - Athens, GA
Small schools - Lexington, VA
Worst - Middletown, CT
Saratoga Springs, New York ( Skidmore College).
Saratoga is a very nice town but I never thought it had many student type establishments.
Blacksburg, Virginia
I agree with Boulder. We have been visiting for years and have met so many CU Boulder grads and professors who say they fell in love with the city and can’t imagine living anywhere else, although they expected to be there only a few years. It has great wether (snow, but not too cold), lots to do, and internship opportunities for college students thanks to the many start-ups and established companies (Google) near campus.
Ann Arbor should be added for sure. Burlington VT as well.
Boston is different…but yes every Sept. 1 we ALL understand it is a super large college town. 
Oxford OH, Columbia MO, Fayetteville AR, Lawrence KS, Manhattan KS
Boulder is similar to Ann Arbor (I lived in both), but with better weather, mountains and of course Denver instead of Detroit. No contest.
Gainesville FL is a great university-centered town with a cool music scene, good restaurants, hills, and lots of trees. Nothing like what most people think of when they think of Florida.
I totally agree with Chapel Hill and Austin, having lived in both places during our graduate school and post-doc years. Charlottesville, VA is awesome, too.
I also second the nomination for Lexington, VA for a small college, and would say that Davidson is more a village than a town, but VERY charming.
Disagree with post # 21’s statement about 50% of town-college.
The influence of UW on Madison is huge, along with having all that goes with being the state Capitol. They are likely the one-two in town. The mile or so up/down (hills)from campus to Capitol on State St. made it easy for students to participate in the sit in protests against what the state was doing several years ago. Oscar Mayer- a distant third eons ago.
In a medium to large city a lesser percentage can still mean a huge impact. Such as mentioned about Boston above. One can also interpret a college town as having great nearby places, not just the on campus sites.
Seconding Blacksburg, VA. The town there seems to revolve around Va Tech, very supportive community complete with shops and eateries, etc.
We visited Eugene (University of Oregon ) and Corvalis (Oregon State University) a couple of years ago when touring schools with our son. Both of them are great, but very different, college towns. Ashland, OR (Southern Oregon University) was also an interesting place boasting both a college town vibe and the Shakespeare Festival. Very cool.
Brunswick, Maine is a great little spot, with good town-gown relations. Chapel Hill’s nice, too.
@domarge And the best lobster rolls!!
Madison.