great city, the bus tours worth doing, and the beach area, built as part of the Olympics refurb is really nice.
I'd 2nd the bit about the pickpockets though. I've been to many countries around the world on holiday and to see footy games, but Barca's the only place I've had stuff stolen.
A simple distraction con at a bus stop, but very fast. The police aren't really interested, as there's no chance of a catching them and getting a conviction, and no-one gets physically harmed.
La ramblas can be crowded, and people stop to look at stalls, mime artists etc, amking it easy to 'bump' into someone.
Keep your money in an inside or zipped pocket if you can, never back pockets, and beware if anyone asks for directions etc.
Be sensible, be aware and you'll be fine.
I know 5 friends who've all been with no problems, but me, I get robbed.......
As I said at the start though, a lovely city to visit. I'm sure you'll have a great time