A serpentine creek that traverses across a golf course at interesting angles is a tremendous feature.
I'm not much of a pond guy, but I greatly prefer if they are off to one side or the other as opposed to the forced carry or the dreaded, "how much to bite off" pond holes. Can't remember the number, but there's a pond hole at Bandon Trails where the pond is off to the right of the fairway and the green seems to roll right into the pond, with an "infinity pool" look.
Ocean holes are most often designed where the water is beyond the edge of the green or the entire hole runs parallel, but the best are the holes where the player must carry a chasm to get the ball back in play or on the green. 16 at Cypress, 8 at Pebble the little par-3 at Sheep Ranch are good examples of this.