Michi......Taxis are very reasonable in Barcelona and tipping is not expected, 10% is considered large and generous. Keep Your money/credit cards concealed....the Subway Stations and Lower Las Ramblas(especially at night) will have pickpockets.....they work in teams (including children and motorcyclists).....Do not dress in your finest...You will be fine...New York City is worse!!!
We will be back in Barcelona in November 2014..We Love the city!!!!!