I'd like to suggest another option for the ERE city. I read secretwealth's list:
1) A lot of farmable land
2) Racially/socially diverse population
3) Well-educated population
4) Good public transport
5) Low taxes
6) Affordable healthcare options
7) High population density
and I realized that the city which I live in now would probably fit the bill. I go to Indiana University Bloomington. Bloomington is one of the top 25 places to retire: http://money.cnn.com/galleries/2011/real_estate/1109/gallery.best_places_retire.moneymag/17.html. It has a cost of living below the national average (93 vs 100).
1) It's basically surrounded by farms. It has enough corn, soy, and cows to satisfy any aspiring farmer. There are orchards, too.
2) It has a racially/socially diverse population due to the university. We have a pretty big Tibetan presence, for example, because the Dalai Lama's brother used to live in Bloomington. The Dalai Lama comes to speak in Bloomington now and again because of the connection. There's a street with a wide variety of ethnic restaurants which range from Ethiopian to Turkish. No one is going to stick out too much just because of skin color.
3) The population is educated in this area because of the university. The professors and their kids make up a pretty significant portion of the town.
4) I wouldn't call the public transportation superb, since it almost never runs on schedule, but you can get around without a car. I did for two years. There's a bus system: http://www.bloomingtontransit.com/System_Map_Aug_2011. There is also a bus that runs between Bloomington and the Indianapolis airport. It costs $15 and takes 1.5 hours: http://www.bloomingtonshuttle.com/. Bloomington has been putting together pedestrian and bike routes for a few years now. It's not uncommon for people to use bikes for transportation. http://bloomington.in.gov/media/media/application/pdf/57.pdf
5) I'm not sure what qualifies as low taxes, but Indiana has a lower rate than CA. Indiana's rate is 3.4%.
6) The healthcare is affordable here. It helps that IU Health is here. IU Med is one of the nation's best medical schools and they have a branch in Bloomington.
7) There's high population density around the IU campus and it's walkable. But if you get even a few miles out, there are farms. Lake Monroe would provide recreational value and it's completely possible to walk to Griffy Lake from campus, even though it's a pretty lengthy hike.
Speaking of recreation, there is a lot to do at IU. One of the best things about going to IU is how many performances there are. A lot of the events done by Jacobs, the second largest music school in the nation, are free: http://music.indiana.edu/events/.
There's fresh, local, organic, affordable food at Bloomingfoods: http://www.bloomingfoods.coop/index.php?option=com_content&view=article&id=74&Itemid=127. A very quick rundown of what Bloomington has to offer, especially for anyone who is vegetarian or vegan [guilty], is here: http://prime.peta.org/2010/08/bloomington-indiana-a-midwestern-haven-for-culture-cuisine-and-enlightenment.
The average house value is $168,600. The climate is classified as mixed - humid and we have the same climate as northern Georgia. http://www.architecture.uwaterloo.ca/faculty_projects/terri/carbon-aia/strategies.html