''The Muppet Christmas Carol'' . I adore that version. The Muppets are awesome and Michael Caine is by far the best choice for Scrooge..
I agree with you, about ''Christmas Carol'' of 1951 with A. Sim.
I also like the movie with Albert Finney as Scrooge (1970), actually I grew up with it!
I suggest the ''Blackadder's Christmas Carol'' (2004) with Mr. Bean. A different, funny version of the story. Try find that version !!
Finally,I love ''Mickey's Christmas Carol'' (1982).