Sean Leary,
You're correct, I meant # 5.
JNC_Lyon,
# 1 at Prestwick may be the best due to its order in the round.
It is a very intimidating first hole, ESPECIALLY without the benefit of warming up on a nearby range, and the rather constant rail traffic that reminds you of the consequences of an errant drive.
Difficult first holes tend to be the most intimidating due to their order in the round.
For those that start on the 10th hole, Yale comes to mind