Greg:
I'm not sure they are the best in the world, but Langford and Moreau's Lawsonia's links course has a very solid group of par 3s (yardages from tips):
-- No. 4, a near-Redan (lacking only the requisite strong tilt of the green), with severe front bunkering and trouble elsewhere. 203 yds.
-- No. 7, which I've argued is Langford's ode to a Short, 161 yds to a severely pushed-up green.
-- No. 10, which Ron Forse describes as one of the hardest par 3s around, 239 yards to an enormous green sharply tilted back-to-front, and strong bunkering flanking left and right.
-- No. 12, 183 yards over level ground to a wonderful green featuring a two-to-three-foot swale.
-- No. 14, a downhill tee shot to a volcano-like green, again severely pushed up from its surrounds. 154 yards.
What is particularly noteworthy about Langford's par 3s at Lawsonia is the variety of clubs one uses. Depending on conditions, approaches to the par 3s for me might be (in order): 5-wood/utility club; 7-iron; 3-wood or maybe even driver with the wind against; 4 or 5-iron; 8-iron.
That to me is a sign of a course with not just holes of merit, but variety as well. Langford really wanted to test the ability of players to hit a variety of clubs into greens, and he certainly accomplished it at Lawsonia with his par 3s there.