Yeah, I think couch maybe getting ever more popular as its so international. "Settee potato" doesn't work anyway:-) Also, I suspect that the Brits don't eat *crisps on their settees as much as US enjoy their potato chips. Crisps seem to mainly be pub food in England - in the sitting room you'd probably go for a cup of tea and a biscuit before you'd reach for corn or potato chips. I think couch is a top verb, btw.