I know Portland is up and coming and all, but I don't think it's quite there yet, for my tastes.
What about Denver?
Hmm ...
As far as society-at-large, I've heard Denver referred to as exemplary of "second-wave immigration" or "inland immigration", which is the phenomenon where the children of immigrants move to other places besides the coasts or wherever their parents first settled when they emigrated to the US. So, it's a melting pot of people from all over the US, but really mainly from California, Texas, and the Midwest, and secondarily the East Coast (mostly the wealthy, the type who own property in the mountains).
It's really a new city, in my mind. I think it's come into its own as a city within the past 15 years. Just about everybody is from somewhere else. It's a laid-back, easygoing place whose "vibe" is mostly outdoorsiness and the mountains, but that has its act together regarding friendliness to business and welcoming everyone. You'll be just as likely to find people wearing Birkenstocks to a business meeting as penny loafers as wing tips. You'd probably want a car, since Denver, much like LA, was built around the automobile, but only recently has amassed the population and money base to build large scale mass transit.
There is an active and vibrant arts scene, mainly visual arts. The new hip thing that's all the rage is is mid-century Modernism and updates on that theme. There's notsomuch music or poetry -- that's more in Boulder, which is about 40 minutes from downtown Denver.
Denver may be in the "up and coming" category, compared to some of the places you've mentioned.
As far as gay life, I've read that Denver has the 7th highest percentage of GLBT people in the US. Now, that's a relative number -- I don't know what the absolute number of GLBTs is, but since the total population of the Denver metro area is about 2.5 million, I doubt the absolute number of GLBTs is higher than the absolute number in Dallas. Its Pridefest is also ranked in the top 10 for Pridefests in the US. The state government is solidly Democrat -- both sides of the House and the governor are all Democrat (at the moment), and civil rights protections are being advanced statewide, the gay marriage amendment notwithstanding.
Capitol Hill is the neighborhood with the largest gay population. It's a huge neighborhood, probably 2 square miles, and has a wide variety of housing types (Victorian mansions, bungalows, high-rise condos, etc) and shops/restaurants/etc. I've read about 30% of the population of Capitol Hill is GLBT, so I don't consider it to be a "gay ghetto" like the Castro in SF used to be -- it's more like a large number of gays are integrated alongside young/black/Hispanic/old/etc, all in the inner city and close to downtown.
I'd say the vibe in the gay world is also easygoing and laid-back, and kind of a cross of the usual campy gay culture with outdoorsiness and the mountains (hiking, biking, camping, Birkenstocks, hiking shoes, etc). Your mileage may vary, others may disagree, still others may hate the place, whatever.
