How Big Should a Rug Be?

atla-082808-rug01.jpgFlipping through the CB2 catalogue recently, we stopped on this picture and thought, hmmm, intrigued by the size of the rug. Since we're thinking about changing our decor and one of the things we'd change is our rug, it made us stop and think...

We've always been taught that a rug should be large enough to at least go under the front legs of a couch to unify the furniture instead of having it look like tiny islands, separated by rivers of floor. But, with two couches and a large coffee table, that puts us in 8 x 10 category if not the 9 x 12 category. Which, depending on the rug we pick (we're currently looking at Pottery Barn's Quinn felted shag in Ivory), can make the difference between "hey, let's give it a whirl" and "give up eating out for two months". What do you think? How big should a rug be?