re: What are the coolest American cities to visit?

Fairbanks, Alaska

Charleston is nice. Folly Beach is worth visiting.

Asheville- Kind of dirty hippie, homeless (Austin lite). Buncombe County provides all kind of services to homeless. Lots of Hep C. Greenville much nicer. Stay there in downtown and maybe drive into Asheville.

Nashville and Vegas are way too plastic.

San Deigo is awesome. Del Mar and Encinitas are nice.

I would add Portland, ME.

For quaint small towns, Dahlonega, GA and Jerome, AZ.

Roanoke, VA is pretty cool. Ballast Point Brewery is awesome.

If you go to Vegas remember that while I base rate may be cheap, they bend you over with a $25-$40/night "resort fee" on top of it.

As for my list:
I loved NYC and Vegas. Utah in May is awesome AF...we landed in SLC and it was 80, the day before we left it was snowing in Ogden.

Bears season ticket holder so I'm in Chicago a lot but wouldn't suggest it with all the shootings. Minny is beautiful but can get hot and humid AF accompanied by the mosquitos.

If you want a list of suggestions, I'd start with this list:
NYC
Boston
Vegas
Milwaukee (especially if you like beer and Harleys)
Minnapolis & Utah during spring/fall
Kansas City
Denver