One place you should not miss is Porto Olympico for some excellent seafood. My recommendation here is to walk among the restarants first to see which one you want to eat at. Most have displays of the seafood and round mixed grills that are worth the money. Most of the restarants here ran about 2000pts per person for four people and 3 bottles of wine. There are some nightclubs amongst the restaurants. If your into claustrophobic places it might be someplace you'll enjoy. Lots of salsa style music.
Another section of town is a street called La Rambla. If your hotel is not on La Rambla to begin with I'd highly recommend it especially if you can get a streetside view. Hotel Royal is very reasonably priced and the rooms were better than the Barcelona Hilton. There is alot of activity here on La Rambla. Street vendors, standing-still mimes (you have to see it to understand it), birds, musicians, etc. Even late into the evening you can see someone playing Spanish ballads on guitar. There are plazas on either side of La Rambla with even more people to look at.
University of Barcelona. If anyone can tell me how I can get a job at this place drop me a line!