I recommend you to visit a place with a "neutral" accent, like Castilla or Madrid (no offense the rest), because it will be easier for you to understand that kind of standard accent, and your spanish will be easier to understand when you use it in other places. Madrid is very expensive, if you have not a reason for being here, you better avoid it and try Soria, Cuenca, Salamanca... not so fashion as Madrid but much cheaper. Enjoy!

a que ciudad vas?

it all depends on what you understand by "Spain" and what are your interests. Let me see if i can give some examples: Saving all distances....if you like places like Texas or New Mexico..go to Andalucia. If you like places like Oregaon or Maine...Galicia. if you like cities like Midwest..Madrid. If you like places like Wyoming, Utah or so...near to the border with Portugal. If you want to feel a bit as in Ireland or north England, Euskadi. If you like places like Dakota or Nebraska, Castilla is ok. Valencia and Murcia if you want to feel some arabic influence without beingsorrounded by arabs all the time. And if you want to feel like in Bayern, Baden-Wuttenmberg or Alsace..the Catalunya i ok. But as distnaces here are low, allow for a lot of variation in short spaces and even some "islands" in between two poles.......

Hello there! About ur question, I should say than beyond than goes to that or what city,It would be more interesting to visit inner towns, coz there u could find for sure where the true spanish spirit lies. In the other hand, there are many regions in Spain, each one with its own culture,but, (pretty sorry for to say so. Alas, no ones knows out there what a Sardana is) the most strongest ones are at northwesternmost, and (that´s remarkable) at southernmost regions.Other regions could be also interesting, yeah, but that´s a fact. Finally both with Madrid, eastern regions have a reputation as wealthy regions. Maybe to know this could be useful, if u wish to have a part-time job,or whatever, during ur stance here. I hope had been helpful! If u have any doubts else, u can mail me here asking about them :) Hasta otra!

Visita Granada, no te arrepentirás ;), luego según el tiempo que estés visita el resto de Andalucía y después para el Norte de España, pero eso ya según lo que estés buscando ver :D.