I say Little Big Planet. Why?
Well first off, Sackboy's pretty much designed to be a weaponized form of cuteness, almost a blank slate for someone's creativity. Which of course means I'd give him a pair of goggles, overalls, a wrench and a construction helmet and say he's the Engineer from Team Fortress 2. Look, I don't have anything against cute mascots, I mean look at Yoshi, Kirby and Pikachu in that regard.
Second, there's a huge thing with a level design mode, and I've been known to tinker with things in Hammer Editor (thanks, Source SDK!) and Warcraft III's level editor. Plus, LBP's levels are all colorful and interesting to look at, which is pretty shocking considering it's on a gunmetal-black system that fully embraces gunmetal-black-and-dirt-brown games. Look, what I'm saying is that THE FUTURE WILL NOT BE BROWN. Remember The Jetsons and how colorful and interesting the future looked? Why did that go away?
Third, I friggin' LOVE old-school platforming. Oh don't get me wrong, precision platforming is now just as annoying as it was then, but there's a difference between tricky spots and trying to jump to a platform directly above you that barely is inside your jump height and if you miss it you fall into an instant-death lava pit. There's something I never thought I'd miss, instant-death obstacles like spikes and lava. Look, all I'm saying is that Platformers shouldn't have gone the way of Adventure games (assimilated into other genres or totally forgotten about) and that lately any attempts to use Platforming games has been detrimental to the genre. LBP...is not one of those games. I'm glad to see that there are some games that still make the Platforming game good as the old-school NES and Sega Genesis games were.
The Great JT still does not call the Sega Genesis the Sega Master System. "Genesis" sounds better, it was called the "Genesis" where he lives so it's the friggin' Genesis!