Just got back from a ten day vacation in Spain. We had a wonderful time, so I don't want to sound too negative, so I'll just say that the food was not one of the highlights. In general, I find Spanish food bland and mediocre and the restaurants are vastly overpriced. You may not agree with me, but if you're in Spain and find you can't swallow another heavy, dull, overpriced meal, then go find the nearest Asian restaurant. There are now many upscale places that serve copious quantities of deliciously prepared food at very reasonable prices.
We ate at a place called Shake in San Sebastian that was great (all Spaniards, no tourists). In Bilbao on the pedestrian walkway in the new town we ate at a place called Asia Chic that was fantastic, huge portions of seafood plus a good bottle of wine for exactly the same price we paid for a truly lousy meal at a Spanish restaurant the night before. Down the street there was another place called Shanghai Cafe that also looked great.