Ratchet. By a country mile.
You seem to be missing rather a lot off your list. I know there's a limit to how many you can put and you've included 'other' for these franchises.
But stuff like Resistance & Motorstorm I'd say you could argue had as much - if not more - of a 'franchise' presence on the PS3 as Heavy Rain or Demon's Souls have (which could be backed up by sales, too). There's other stuff like WipEout; Twisted Metal & Sly Cooper as well but I suppose they've all only made one appearance each. If WipEout was included I would have voted for that, but I'd rather single out Ratchet than vote for it among 'other'.
And of course, you're forgetting the big daddy of PS3 exclusives, but I think you've spotted that now :P
Anyway, rant over.
