I think team rooms are a problem if, and only if, they are permanent. I've worked in cubicles, open floors and permanent team rooms and in the later all people did was to use the privacy to surf the web, talk about stupid stuff they would not dare to mention in a open floor. It made it very tricky to concentrate, but at least the problem was concentrate and a talk with the team leader / manager would usually quiet thing down for a while.

Ad-hoc team rooms sound like a very good idea though.