I think "the greatest tee shot in golf" is probably a hole #1 somewhere. The first tee shot of any given round has a special significance. Balls are thrown in the air, partners are chosen, and the pre-shot jokes are a little funnier, as everybody mentally prepares to play. Jack Nicklaus wrote that the most important shot of any round is the first tee shot, which sets the tone for the entire round.
Without having played there, I have to believe the first shot at The Old Course is as good as it gets. Of the ones I've played, I like the first shot at Ballyneal, Sand Hills, and Riviera best, with honorable mention to The Kingsley Club, where the reward for a well struck drive is considerable.