To give a sense of the variation across the country, John Phipps recently blogged about the cost of land in Illinois, he paid his sister $4,500 an acre, a neighbor sold for $5,200, and there's a recent rumor of $9K. Compare this LA Times article on Ventura county, CA quotes a figure of $61,000 (orange groves are being replaced by strawberries and other high priced produce).
I remember the Iowa state specialist who back in 1981 was moaning about having bought a "farm too far". I wonder how many land buyers this time around will be caught out. Or have things fundamentally changed?