Well, I would guess that AA has superior legroom in coach, but other than that, and I'm sure a small handful of other carriers, Air Canada seems to be among the roomiest. I flew on their A330 and was very impressed. More legroom there than on Air France, British Airways or Lufthansa, or at least that's the impression I got. Their A320's would be standard with other carriers though, and that is quite roomy for what it is.
"it's kind of like an Airbus, it's an engineering marvel, but there's no sense of passion" -- J. Clarkson re: Coxster