One of the great benefits of being trained in Earth is the great attack spells. Hurl Boulder is good, but the shorter ranged Hurl Rock is awesome in my mind (excellent damage dice to cost ratio). I know that my opponent will be closing with my squishy Wizard, so a range 0-1 attack spell is fine. Also... Earth attacks currently do not have any specific reducers that I can think of. The Elemental Cloak is favored for its reduction to Fire and Lightning, just as the Dragonscale Hauberk and Storm Drake Hide are. Your opponent will generally take all 5-7 dice that you throw his way with Earth attack spells.
In addition, if you do go a little heavier on attack spells, then I would suggest a Hawkeye enchantment. You would add one die to every ranged attack... even the Wizard's Arcane Zap. A one mana cost spell doing four dice of damage is pretty awesome.
If you decide to stay with many creatures, then you might want 3-4 Teleports... mostly for moving the enemy Mage either away from guards or into a zone where there are several of your high attack but Slow creatures (Iron Golems and Devouring Jellies, for example). I don't know that having more than two teleports in other cases really pays off.
You will find spells that you really love and really hate. I am more a fan of Shift Enchantment than most, but I feel that it is at least as versatile as the Enchantment Transfusion. They each have their niche. Shift Enchantment can preserve the Harmonize on your spawnpoint so that you do not lose your mana generation. Enchantment Transfusion can allow several neat tricks (there are threads just on that subject).
I have played serious mana denial as an Earth Wizard before, but found that I overindulged in it to the point where I had no way to finish the opposing Mage off at the end of a game and/or didn't have enough of the right tools to use in other specific situations. Diversity, I believe, is the key in any spellbook. Having some mana denial is ok as a tool, and especially useful against specific Mages... but you don't want to overdo it.
If you are going Mordok's Obelisk and Suppression Orb (which together about kill a Beastmaster and hurt a few other Mages... Priestess and Necromancer primarily), then you will not want a Creature focus in your book. I'd either get rid of one or both conjurations or limit yourself to 4-6(?) mid-sized Creatures. My Earth Wizard includes MO but not the SO, and still only has four Creatures. Of course, there are more than a dozen attack spells in the thing also.
If you want a ton of creatures... go for it. An atypical spellbook may take some more experienced players by surprise. Note also that other Mages are more efficient at heavy Creature play, however, so if you want to play that way, you might consider switching to a Beastmaster or Necro or Priestess, for example.
Be aware that only Arcane creatures can come into play via the Gate to Voltari, so you might also remove the Gate if you find yourself removing too many Arcanes from your spellbook.
Anyway, those are some of my thoughts... hope you find some of this useful. Whatever you do, however, make it a book that you enjoy playing regardless of what everyone else says.
