Freezezy Peak. Hands Down.
What's better than being reminded of your childhood?
Being reminded of Christmas, and your childhood.
But from a totally analytical and artistic standpoint...
Then I'd say Click-clock Wood. You know, it has the whole masterpiece of level-design thing going for it. I can play it a million times, and it never gets old.
"God, Ted. D'you remember that fella who was so good at fashion they had to shoot him?"