18th hole at Pine Canyon, a Jay Morrish design in Flagstaff, AZ, is a 460-yard par-4 that falls about 70 feet from tee to green.
But that's nothing compared to the mother of all downhill 18th holes, which i just was at: TimberStone, in Iron Mountain, Michigan (Upper Peninsula), designed by Jerry Matthews and Paul Albanese, where the 620-yard par-5 18th falls 175 feet.