Of course you would pick 4 of my favorite episodes to choose from again lol.
This again was a tough call, but I picked SS.
I had a soft spot for Andy when we got to know him. Plus the episode was funny and serious on several levels for me. From the Moby Dick bong, to viewing Dean's face while Sam was talking to him in the car in the beginning of the episode.
You could see it was killing him knowing the secret his father had left him burdened with and trying not to let his brother know at the time.
Andy was I think my favorite among the other "chosen ones". His brother may have been nutso, but I felt Andy had a good heart and didn't want to hurt anyone.
Big factor for me was the brothers still had that very "close bond" that I miss seeing now days in a few of the recent episodes.