The cheapest city to buy a house is Butte, but there are reasons... (if God were to give Montana an enema, he'd do it in Butte)
Summers in all four areas are great. Spring and fall are nice... Bare in mind I've seen it snow in every month of the year though. Spring really doesn't come until about now and fall is in full swing by the day after Labor Day, with winter pounding in by Thanksgiving.
I just saw a story that the fastest growing town is St. George Utah, why I couldn't guess.
I really don't like the Salt Lake area, with the mountains to the east it can get real bad air pollution and the roads are ugly crowded (that from a guy that regularly drives in Seattle)