LittleBigPlanet has been on every PS3 owner's wishlist for 2008.  I was lucky enough to pick mine up from Gamestop yesterday and I am loving it.  My girlfriend and I are about 30% through the campaign.  Co-op is definitely a must for this game.  I have yet to dive into any creation or online worlds, but I will do so shortly and share some feedback. 

I still have that Trophy-whore mentality, so I will be touching the far ends of the game to get as many of them as I can.  I also have a few ideas for some pretty sick levels I want to attempt at making once I unlock everything.  Not to mention, the Playstation Eye is starting to look more and more appealing.  What, with the Sony EyePet and now LBP integration.