Johnny V.
Yelp
True or not, I was told this was the heart of La Rambla, and it's the only plaza that I would even think to review. Although I hadn't planned it and I didn't know until I got there, there was a festival going on coinciding with the days I was in Barcelona, so there were always tents up and stuff going on, and there was a large stage erected for the occasion as well. Sorry, but I actually wasn't too interested or impressed with the different shows and such that they had going on--the only thing I had enjoyed was a group of singers singing songs that were all in Catalan. I still enjoyed the plaza in general, including the nice but VERY overpriced minimall-type-thing, but mainly as a respite from the crowded and disorderly ways of La Rambla.
There are fountains, flowers, statues, and open spaces so we found ourselves here several times a day, just resting, chatting, and enjoying ice cream or fresh fruit. It's really the only plaza that I enjoyed in and of itself; often, great plazas have great things along it's perimeter (stores, restaurants, cafes, etc.) but I don't remember much about the perimeter. Perhaps because the street is so busy and crowded--with both people and businesses--the plaza becomes an island of escape, not necessarily a hub, and I really appreciated and enjoyed that aspect of it.