Barcelona is fab. Just walk up Las Ramblas and around the old quarter. Look at the Gaudi architecture - Sagrada Familia, Casa Mila and the other Gaudi house just off Las Ramblas (which i reckon is better than the Casa Mila) also there's the Parc Guell. If you like art, Joan Miro museum a bus journey from the centre, Salvador Dali museum a couple of hours away in Figueras.
Around Barcelona the locals mostly speak catalan, but everyone understands standard US high school spanish, and most of them english, certainly in the touristy spaces.
don't waste your time visiting ibitha or any of the beach resorts for the english and german sunseekers, but madrid and grenada (and lots of other places, as well) are all worth exploring.
