I applied to Wisconsin to work with James Sweet, Florida because my sister is in the grad program there, JHU to work with Ben Vinson, Columbia to work with Christopher Brown, BU to work with John Thornton, and Harvard because I wanted a second school in the Boston area and Bernard Bailyn encouraged me to (though having not been admitted, I am questioning my judgment on that $105 application).
If you're familiar with any of those names, then you know them probably as people just as qualified in African History as in Latin American History. Thornton has been my undergraduate adviser here since I was a freshman. He put me in contact with all of the professors I wanted to work with at grad school. I also contacted Jane Landers at Vanderbilt, but for some reason that now escapes me decided against applying there despite the fact that it is much closer to home than anywhere else I applied. For some reason, I got a number 6 in my head and that was all the grad schools I wanted to apply to. If I had it to do over, I would drop the Harvard application and add Vanderbilt, Texas-Austin, and Berkeley and possibly Tulane or UCLA. As it was, I only applied to schools where Prof. Thornton specifically told me someone to contact (minus Florida, which was entirely to be near my sister).