Which of the unis would provide the best location?

[Patrick del Poker Grande]

I think the best advice would be for you to look over and pre-screen some of these down based on their academic credentials first. Then, actually talk with some professors and find out who you'd like to have as an advisor. Find out who's strong in the exact area you want to go into. Then, once you're down to a handful of schools, bust out on a tour of the United States and physically visit each one of them. I think your answer will be pretty clear at this point.