Spaniard here. Nice place, cheap, sunny, you know the drill.
However, good luck if you need a job, we have record unemployment rates. And you'll need a miracle if you don't even speak some spanish. I'd say, if you choose Spain try to find some company related to healthcare with an international department in which english is spoken to hire you.
It is very difficult to live with just english in countries which perceive themselves as having "strong languages" like Spain, France or Germany. This doesn't happen in Sweden or Norway. In fact I swear every goddamn swedish speaks perfect english.
Dunno about visas, though. Then again, finding a job before you reach the country always makes things easier.