We're a group of 5 - 3 adults and 2 kids - so hotels were looking really awkward, what with the European restriction on the number of people per room (2 adults and one child seems to be their absolute limit).
So I've been having a great time looking at all the vacation apartments available in Barcelona, most of which are actually less expensive than for a group our size than a mid-range hotel. I followed a link someone posted in the Med Cruise thread, bcninternet (you'll have to infer the html bits bracketing the site name, as I'm new here and still can't post links), and found a number of appealing listings there, but also discovered that that site belongs to an association, Apartur (again, bracket that with "www" and "com", along with appropriate dots), through which you can access a huge range of listings.
I did end up booking an apartment through that first site I mentioned, though. 3 bedrooms, 2 baths and a kitchen for 3 nights, situated near the port and the Gothic quarter. With temperatures in the single digits around here, I wish I could be there now!