there's different aspects of clutch. there's the clutch of who do you want to run a play for to take the game winning 3? who would you want to take the open 3 to win the game?
but clutch is also who you'd want in on the floor in a tie game with 2 minutes left. who's going to make the plays down the stretch to help his team win the game?
clutch is who's hands do you want the ball in with a final possession and a chance to win?
horry and miller are good picks for situation 1. for situations 2 and 3, horry i think doesn't rank as high. miller probably still does, although less so in situation 2, imo, because his game isn't that well rounded where miller's going to make the big steal, get the big rebound, make the defensive stop, create the open shot.
however, there aren't too many other players out there with too much of a track record on making the big plays, especially in big games.