[ROBINDESBOIS]

I advice you to go to cities around Madrid, such as Segovia, Valladolid, Avila or even Burgos. Bilbao and San Sebastián are good options too, Alicante too. Madrid is Ok too. Not many people speak good English to answer you in English. But there are lots of Americans. Go to Castile, their diction is perfect, the cities are cheap and most people do not speak English, and most important there are not many americans to speak of. I live in Madrid and somehow or other, Americans tend to flock together, I know quite a lot. And many of them run businesses here. Segovia and Avila are so close to Madrid that you can visit the capital some weekend.
Avoid living in Andalucia because their accent is not good, I mean not very clear for a Spanish learner . Avoid Cataluña too, they are not very happy with the Spanish language.