I'm renting a room (doble bed 1m35cm, with heating) in my attic (with elevator!), right at the center of Barcelona, in Plaça Universitat, 5' walking to Plaza Catalunya.
It's a 2 bedrooms attic with a beautiful terrace (the best view of the city. Promise!), plasma tv, wifi connection, wooden floor, and a lot of light. It's very clean, quite, and one step from the Rabal and Sant Antoni neighborhood.