I don't think LBP will be very big in terms of sales. I think it will be pretty awesome though; being able to import material and create your own game, sounds like an awesome geek pastime. I envision importing images of my kid's favorite toys, recreate them with simple shapes and place them throughout a basic platforming course. I'm not sure how deep it really goes, but it sounds pretty damned full featured, and easy to use. So, fun, but hardly something that will draw in much of a new audience.