Love Barcelona. Went the last three years in a row. Bus tours were brilliant, the blue and red routes both as good as each other and they run like clockwork. Sagrada Familia is a must even just from the outside. Not sure if the new Nou Camp is open yet, they had the plans sitting there when I was over. Cable cars are worth a visit, brilliant view from the top. Look up MAKAMAKA burger bar on the beach front.
Cheers, Stevie.