Skyrim, actually. It probably helps that there aren't any trophies for the harder difficulty settings, so it was really just a matter of playing for long enough. That's the only game I've got platinum for, though. Other than that, I'm one trophy away from getting platinum on Dead Space 1, which is the one for beating the game on Impossible. It's not like I haven't tried to beat Dead Space on Impossible, I just got to a bit in chapter 9 where I knew I was going to be swarmed by a horde of Twitchers, Leapers, and Exploders and lost my nerve, so that 91% in my trophies collection has been mocking me ever since.