Omfg, Lego Back To The Future and Lego James Bond would both be awesome!!!
Matrix would also be cool. Am also really looking forward to Lego City Undercover, although I suspect the name change from City Stories to Undercover would stem from Take Two having problems associating the GTA franchise/trademark with a Lego game so hopefully it's not going to stop the game from becoming Lego GTA.
I'd quite like to see other game franchises getting the Lego treatment - Zelda, Metroid, Gears of War, Half-Life, God of War, Splinter Cell and Assassins Creed would all be excellent.