For Story, just for SA, based on how enjoyable I think they are overall and not power alone. I'd be happy to elaborate on my choices, if anyone's curious. Wii version, by the way.

Tempest Dragon

Eye of The Storm

Siren Griffin

Typhoon Titan

Vine Virtuoso

Nut Crafter

Floral Defender

Forest Ninja

Bone Crafter

Nether Welder

Vampiric Warrior

Fear Eater

Pulver Dragon

Earthen Avenger

Crystaleer

Sandhog

Soul of The Flame

Flame Lord

Pyromancer

Volcanor

Glacier Yeti

Tesla Dragon

Captain Crustacean

Water Weaver

Sheep Burner Spyro

Conjuror

Ultimate Spinner

Marauder

Clobber Troll

BattleDozer

Clockwork Dragon

Golden Money Bags