Markos Moulitsas (founder of Daily Kos) asked for suggestions on nice places to live. My suggestion:
I'm an Albuquerque native, but I'm quite fond of Salt Lake City. The place has what you want (except warm winters) and is more diverse than people imagine. The Mormons travel overseas on missions, so there is a better-travelled populace than you can find almost anywhere else that is interested in foreign affairs. The leftish crowd has more to work against in SLC, right in the middle of the belly of the conservative beast, than you'd find in most of the country (even the South) so there is a real vitality to the work: it MEANS so much more! Small industry and industrial arts are better-respected there than in the Sunbelt (after all, Mormon culture is a derivative of the culture of northern New York State, where Yankee ingenuity means something). Crime rate is very low, and the people are nice. They believe strange things, but there are no nicer people anywhere!