You should select a climate with 20-30 inches of annual rainfall. Less rain is not enough water for the plants and the soil is under-developed. More rain leaches nutrients from the soil and leaves the soil in an acid, overly-developed condition. http://www.soilandhealth.org/01aglibrary/010141.soil.fertility.animal.health/010146.albrecht.animal.health.pdf
Dr. William Albrecht noticed that men enlisting in the military were rejected 30% if from the midwest while 70% if from the southeast. Large herds of buffalo thrived off the protein rich grasses of the midwest (while small groups of small deer populated the east). Higher protein content wheat can be grown in the midwest compared to the east. http://www.soilandhealth.org/copyform.asp?bookcode=010143price Its a free article, you just have to sign for it.
I've found this document to be an excellent read, as well, for the general knowledge of soils http://en.wikipedia.org/wiki/Soil
Albrecht devoted his life to the study of health as related to the fertility of soils. I would read anything by him if you're shopping for soil on which to live and be healthy. http://en.wikipedia.org/wiki/William_Albrecht
It may also be wise to select a climate which has a long growing season, but also has a winter. Many fruit trees require a certain cold period. http://en.wikipedia.org/wiki/Chilling_requirement
I don't consider fruit to be such a concentrated nutrient food http://ndb.nal.usda.gov/ndb/search/list Whole grains, nuts, meats, and leafy greens seem to be at the top of the list in nutritional density. However, fruit does taste good and has antioxidants not listed on the USDA's site. http://www.whfoods.com/foodstoc.php
It may be easier to select what you want to eat and then move to the place on which it grows best. Albrecht also noticed plants grow naturally in the soils they specifically like best. He recommeneded against crop rotation, pointing to evidence that crop rotation reduced soil fertility faster, additionally, that plants grow better in soils that happened to naturally be "tuned" to the specific plant. Moving the plant from its ideal location to another location for the sake of rotation wasn't optimal. I'd love to post the reference, but with the vastness of his writings and much of it being copyrighted (no google search), I am unable to find it. When I do, I'll edit to include.
All this being said, technology can provide means to live in an area of the country where the climate isn't ideal. Lime and fertilizers can be applied to bring acid soils up to par, should you choose to live in a higher rainfall area. If you want to be totally unreliant on technology, then you will have to seek out soil to provide you with the health you require. Even then, working the land and removing crops will require you to add something back to the soil. Technology certainly makes this easier, however.
Lastly, it may behoove you to study future climate trends in light of global warming. http://www.youtube.com/watch?v=_nzwJg4Ebzo The changes in the jet stream have produced prolonged drought or prolonged heavy rains in some areas of the country. This makes gardening especially challenging. Selecting the best place to garden based on past data can be misleading.
If you have any other questions on this topic, or need me to elaborate on something specifically, let me know.