I have been in Boulder (or nearby county) for almost 10 years and I must agree with those who see it as a highly educated, liberal, progressive, clean, healthy city (the list goes on...). BUT, it is way expensive relative to the available jobs (especially if you want anything other than a condo) and the students can be annoying. Many of them seem to treat it as their own little party palace with little regard for those who call it home (I guess this applies to any college town). My wife and I (jokingly) say under our breath every spring (to the lingering students): "We can't wait until you're gone!" It's not really that bad, but the summer is MUCH better in their absence. Of course, much of the economy depends on the university, so go figure.
The people are generally nice, if a little self-centered and detached. And there is a kind of attitude of elitism that grates a little. I am tremendously liberal and live as green and sustainable a life as possible, but everyone around here is so damn proud of their way of doing things that you can begin to loathe Prius drivers as intensely as Hummer drivers.
Lots to do if you like the outdoors and many shops and ways to spend even more money. I am an artist and let me say that if you like contemporary art, you're out of luck unless BMOCA or CU has a decent show up. They deserve credit for making an effort, but most people here want landscapes and painted ponies and that's what they get. Luckily, Boulder is essentially a suburb of Denver (yes, I said it) which has the beginnings of a solid art scene (even if it still has a long way to go).
I am originally from the midwest and have lived in St. Louis, Dallas, Denver and Kansas City and even though it seems odd; a place like Kansas City or Chicago can seem like a breath of fresh air.
I've never spent any serious time on the East coast (known for its grime and rude citizens), so take that into consideration regarding my comments.