I would say that Nashville is liberal by Tennessee standards but probably conservative compared to many other larger cities in the country. You'll probably find the occasional hick or bigot, but I don't think that's the norm for people here, at least in my experience. As you may know, Nashville is projected to grow quite a bit over the next ten years, and there are already a lot of people here who have moved here from other areas, so you'll find people from a good variety of backgrounds.
Housing has done pretty well here, even through the financial crisis. I don't think Nashville took nearly as much of a hit as a lot of areas did. As far as current costs, the areas that I find most desirable here, and the most expensive, are the ones that are closer to the downtown area, which is where I work. Like many cities, a lot of the urban core and early streetcar suburbs have been revitalized and are popular with a lot of people. The areas farther away from town are cheaper, but then you have to deal with traffic. While it's not as bad at this point as Atlanta, it's spreading out more and more. I don't know what "expensive" is for you, but I would think you could get a modest but decent house in an area that I like (realizing, of course, that you may have different preferences) for maybe $275,000-$500,000. There are still bargains in these areas, of course, if you don't mind a fixer-upper or a place in what my real estate agent likes to call a "transitional" neighborhood. And if you don't mind more of a commute, you could get something bigger and nicer for less.
As far as public schools go, I don't have kids, so I really don't know much about that side of things.
Other than that, there's a lot to do -- good restaurants, pro football and hockey teams, a few universities, fairly close to some good outdoor rec opportunities -- and the people are pretty friendly in general. Oh, and no income tax, which a lot of people like, although sales tax is higher than a lot of places in order to compensate.
You could definitely do worse.