You can take a city break and a beach holiday at the same time!
BARCELONA has got good beaches (with all the usual beach attractions, such as watersports, boat trips, pedalo hire, sunloungers, beachside bars etc) but it's also a shopper's paradise, a Mecca for culture-lovers, packed with superb restaurants and vibrant with nightlife. (There's also an excellent, cheap, fully-integrated public transport system, and it's easy to get to the Costa Brava beaches just along the coast). In short, it's whatever you want it to be.
Barcelona is easy (and cheap!) to get to, with easyJet and Ryanair (among others) both operating to the main ('El Prat') airport, and with Ryanair also flying to Reus and Girona (both of which have direct coach links to Barcelona).
http://www.barcelonaturisme.com/English/
Chris