Like Born2beagator, I maxed Fire Sphere, Firebreath and Dragon Spirit. I also maxed Dragon Burst, which came in handy a couple times, but maxing it was due more to an abundance of skill points (never tried the summon, shield or polymorph spells). Eventually I removed all equipment except Bone Dragon Cuirass (+40% hit points) and Bone Dragon Leggings (+40% offense), since the rest just had skill bonuses.
