OK, Tucson has been mentioned several times. Chris McMillin gave a good appraisal from his standpoint having just moved there several years ago. Let me add a few things using Fred's criteria list above, realizing some of this is repeated in several posts:
Weather- essentially, you can fly all year. Yes, sometimes the wind blows and there is inclement weather, but few places are as desirable. There may be several days when the temperature gets below freezing. And as has been mentioned, mid to late summer, the temps can get brutal. You learn to do things in the mornings and also learn to park in the shade whenever you are out. (But Tucson is generally 5 degrees less than Phoenix in the summer.)
Crime - for a small city, I cannot quote any statistics, but crime is not a major problem there. There are some areas to avoid, as in any city.
Taxes - Arizona and Tucson are certainly not in the higher percentiles.
Politics - After living in LA for 25 years, anything is a relief. Arizona and Tucson have their problems, but compared to many other places, this is of negligible concern.
access to internet - no problem
Access to good hwy for commute - Interstate 10 goes right through the city.
Local codes (HOA concerns) Depends on the area. Many areas have no HOA's
Gun friendly...2nd amendment - as mentioned above, AZ has an open carry policy.
Good school system - might need to do some research here. University of Arizona is in the city. With it is an extensive medical/hospital system
Restaurants - Not lacking
Ethnic Mix.... Well obviously, there is a strong Spanish influence throughout the area.
As mentioned, Columbus park has 3 paved circles (though one is virtually useless now) and room for 4 grass circles. The city maintains the grass areas and is friendly to the CL fliers there. Several contests are hosted there each year including VSC of course. Phoenix is a little more than an hour drive. Between the CL people in Phoenix and Tucson, there is a good amount of CL activity, specifically Stunt. Combat is represented as is Carrier. If you are into RC at all, there are several really fine dedicated RC sites in the area. There is still a hobby shop there that really qualifies as a pretty good hobby shop, though CL is not a major portion of its stock. The FF people also have a site well away from population, buildings and trees.
One thing not mentioned is the altitude. Columbus park is about 2,400 feet. On hot days, the pressure density starts to resemble a lot higher altitude. However, the altitude does not affect the way models fly too much compared to say LA at sea level. The stunt pilots there in Tucson handle the altitude very well. (Certainly not like the 6,000 feet I have here in Colorado.)
Cost of housing and living expenses can be reasonable to whatever level fits your needs. There are many developments on the edges of the city where you can really be next to open desert with great mountain vistas, terrific sunrises and sunsets, yet can be just minutes from downtown. There are many entertainment venues in the city. The University provides a wide diversity of programs. Also, you can see some of the best college basketball there if you can get a ticket to the games. It is a one day drive to LA with its several contests. A bit longer to get to central Texas.
Keith