Guardian - I love Ubisoft's open-world shooter, and it's because the systems are prepared to take a backseat on my jeep ride into violent pirate adventure.
(Far Cry 3, PC, PS3, Xbox 360)
Having games be a little more flexible or sandbox like is definitely something I hope we see more. Granted, this is still an "on rails" sort of game, but flexible enough on it's approach that it's not always the same thing during every session. I likes.
It has an editor... I tried fooling around with it one time but I was so lost trying to figure it out that I gave up on it. There's some pretty creative user maps out there... a mock up of bikini bottom just to give you an idea but I've also joined a room that was just a giant penis with palm tree pubes and goats everywhere. People are strange.