It depends upon my mood, but I had to go with Brian and the Beach Boys for two reasons:
1) Pity
2) I think the final 15 seconds of A Day In The Life of a Tree is some of the most beautifully recorded harmonies Brian ever did and I just want it to last far longer than it does.
I just felt the same way.
I also love the harmonies at the end of You Still Believe in Me. Wow the first time I heard that I wanted it to last forever but it's so short!