HYmn tunes - to change or not to change?

Richard Hall over at Connexions has started an interesting conversation around the use of hymn tunes and changing them. A number of folk have commented and this may be a topic I will revisit but I felt I had to comment on the use of the Muppet Show theme music for the hymn 'O Jesus I have promised' which had been suggested. I am sure my wife thinks I have gone mad as I have just downloaded a midi file and sat here singing along to the Muppet them. I think she is worried I might use it at one of our more traditional churches - now there's a tempting thought.