One of the best places to have a good time while eating some delicious tapas is La Xampanyería, place of worship for "tapeo" (going "de tapas") fans and temple of cholesterol for the people not really into vegetarianism.
This place, existing for years already, is located in a narrow street neighboring Port Vell in Barcelona and everyday it gets packed of clients craving for some tapas or some sandwich and to have with some cava or delicious rosé wine of the house.
One of the strong points is the informality of the place, there is no table nor waiters, just a counter with "distributors" taking care of the clients in a very attentive way. This place looks more like a bodega than a restaurant and opens from Monday to Saturday. The variety of tapas and baguette sandwiches is uncountable: pork in all forms, cheese, omelets, frankfurt sausage, everything very greasy but incredibly delicious, a craving many dare to taste.
The best is to go with friends and stop in front of the counter and start ordering some tapas as a starter and a good bottle of rosé wine and then bolt a baguette sandwich and go on with the party of saturated fat until your stomach cannot take it anymore. Maybe the best part of this place, apart from flavors and smells, is the price. Each sandwich doesn't cost more than 3€ and the tapas and drinks neither.
With all this, La Xampanyería is a place you MUST go to when visiting Barcelona, also for those living there it is impossible not to go once in a while. Good things come in small packages.
Taller de Tapas is for me one of my most fetish restaurants for dinner when I go to Barcelona. There you can eat traditional tapas in creative ways. In addition, the menu is extensive and diverse. Come on, there's something for everyone! The key lies in the wine, if you do not know which one to choose the waiters make good recommendations. Be sure to call ahead so that you don't have wait when you get there.