Not one of the most templates ever but one of the most at LA+1...Anthropomorphic Horned Lizard (LA+0) White Dragonspawn (LA+1) Dragonborn (LA+0).

With +6con and +6wis, no stat loss, +7 natural armor, small, 30ft Fly speed (Average Maneuverability), your choice of Dragonborn aspects and with no racial HD after class levels it seriously made a wicked divine caster.