Following vonbontee's suggestion that this deserved its own thread after I gave a choice of Paul Simpsons or George Simpsons in the "Choosing Between Two Things Things" thread, I'm starting one.
Three things to think about I think.
1) Which of the guest appearances is the most essential to the story/best?
For me the most essential is Ringo's. The whole story of that episode revolves around Ringo. Lisa becoming vegetarian. Hmmm... would have happened with or without Paul and Linda, they were just beautiful icing on the cake. The Be Sharps, always waiting to be done given all The Beatles' nods in The Simpsons.
The best? I love ...