I think it is a very creative franchise. I mean, to do the entire game in Lego is a feat! And they add their own little twists and humourous game jokes.
I can't wait for Lego Batman, still need to buy Lego Indiana Jones, but maybe we can wait for a Lego Spiderman, which'd be cool!
Just remember, the Lego games are a heck of a lot better than the games with actual, non-lego sprites and the sorts.