According to a study from MIT, The Future of Solar Energy, the United States is expected to be able to power its demand for electricity in 2050 from 33,000 square kilometers of land (http://bit.ly/MIT-solar-future). That may seem like a lot of land, but it should be considered in comparison with other areas. We have about 20,000 square kilometers of rooftop, for example, not enough to power our country. On the other hand, we have 10,000 square kilometers of land devoted to golf courses, so it is 3.3 times that amount.
It happens that the amount of land we have devoted to coal mines is 34,000 square kilometers. Coal mines are often eyesores, but they could be largely converted to solar power. Doing so would hardly make them worse.