I would absolutely hate to see a remake of this movie. Why not a sequel? It would be awesome to see Michael J. Fox return as Marty in any capacity, even a cameo, and the same can obviously be said for Christopher Lloyd as Doc Brown. Rant aside, the actor that came to mind with regard to the subject at hand was Mathew Lillard. He has just enough oddball energy to pull it off, I think. I think RDJ could definitely pull it off, as well.