I can not recommend the flat of eli and agus enough:)
The flat looks exactly like on the pictures, its spacious and was very very clean. The location is PERFECT, you can really see the Sagrada Familia. The neighbourhood is nice, even a Mercadona (best supermarket of spain ;)) is just arround the corner. My parents also found some bars to have a late night beer there..The best sights of barcelona are just in walking distance, we didnt use metro or bus at all. Next, Agus was very very friendly, he speaks a very good english and recommended us the best things so see in 3 days Barcelona, and he was absolutely right. The fresh made bread they left us there was delicious and just perfect for having lunch, we where starving :P What else... the kitchen is well equipped with basic things for cooking etc. A cute balcony, two bathrooms (perfect for a family with 3 girls) and well, we were so satisfied. Defenitely the best place to stay in Barcelona, we would come back ;)