Auto-translated
My favorites are air and water. I play mostly as Haven, and they almost always have a powerful prayer spell, and dispelling magic is useful for everyone. Don't forget about healing, weakness, bless, and clone (I annoyed my friend by cloning a group of 15 archangels:smile08:), and teleport (who said that knights don't participate in taking castles?:smile10:). As for air, my favorite spells are haste, lightning, and destroy undead, which has saved me many times in battles against other players (and why does everyone love undead so much?:confused:), and there's also flight and dimension door.
Earth is in third place with its slows, shields, stone skins, city portal, antimagic, and earthquake (I maxed out earth, and catapults are no longer needed).
Fire... it's not bad, but I rarely use it, only when I play as Inferno, and even then, not always.