I'm gonna go with Rick Adelman. Took Portland to the Finals 2x, losing once to the Pistons, another time in 6 games to the Bulls while coming within 3 minutes of pushing them to a Game 7, the WCF once where they lost to Magic on one of the greatest/smartest plays I've ever seen (the rolling the ball down the court to run time out in a 1 point game in Game 6), completely raised the Kings from the dead taking them within OT of the Finals (which they would have won easily) and had pretty good teams over-achieve in Houston.