Super Mario Galaxy easily wins imo. It has better game mechanics, the gravity effects were just awesome. The music was amazing and the level design was great. I also loved the use of colour in that game. Very artistic.
The thing about LBP is that I couldn't get myself to complete it even with 4 people, it was lacking something to motivate me to get to the ending. I never attempted to make a level though, not that fond of level editors. Maybe that's why I don't think it's as great as others claim it to be.








