funes, MANY of the rooms have balconies and I ALWAYS ask for streetside rooms with balconies just because it's something unique for me and I like to feel like I can get outside while still not leaving the room.

Street noise can be a problem on, say, New Years Eve, Carnaval, or even Halloween night but since you're on the TOP/5th floor (or 4th floor as they call it in Spain) and since the windows have triple panes (a recent upgrade to all or most of the rooms) I doubt it will be a problem at all. BUT since I haven't stayed there personally - only toured it several time - hopefully Mongo or the others can better advise you.

Good luck and enjoy! Saludos, MadridMan