I just returned from Barcelona yesterday. In my opinion the best part of city to stay to get to know the city from the local's prospective is in the L'Eixample neighborhood. It's where the middle and upper middle class live, not a tourist destination. Tourist sites are easily accessible from this neighborhood by taxi. While guided tours will give you some historical information, you will find out quickly that the most touted tourist attractions are sold out days, or even weeks in advance so you will not be able to visit them. Furthermore these attractions mostly have timed visits, so that means you must pick the available day and time to visit in advance. This even includes the popular park, Palau Guell. These sites, like the Sagrada Familia, are so popular with tourists that the locals don't bather visit them anymore since the crowds are overwhelming. My suggestion is to read Steve's information on the attractions in his Best of Spain book published this year then take the two day Hop-on-hop-off City Tour Sightseeing Bus and ride both routes (east and west) without getting off. By doing so you can see the size of the crowds and determine whether the size of the crowd warrants a visit on the second day.