360, for the simple reason that I don't have a PS3 and have no immediate plans to get one.
I don't get the disc-swapping thing as a criticism. I swap discs every time I want to play a different game, after all. Getting up in the middle of a game to change a disc isn't any worse a deal
And I rarely play something exclusively these days, so I'm unlikely to actually want to sit down and play right through something from start to finish without switching to some lunatic buggering around in Assassin's Creed II or trying to get into some Salarian panties in Mass Effect 2 anyway.