I can't list a specific favorite but I saw Treasures from the Deep earlier this week. It was nothing out of the ordinary that Compo bothered Nora to the point where she threw a bucket at him. What was funny was it was his preconceived plan to get the bucket. Then there was his concern over taking care of the bucket that was thrown at him because he was planning to return the bucket.
Another scene that sticks out doesn't just involve Compo, but involved Foggy and Clegg as well was The Mysterious Feet of Nora Batty where the guys are using the pole to get Nora's shoe size while she is on the ladder.
And lastly, one I mentioned before, "The Last Surviving Maurice Chevalier Impression" where Compo's televised performance starts with a close up of Nora's photo and Nora is watching with a big smile in the cafe.