I like doing Life to Satyr, Ice to Tower, and Balance to Weakness. I also get Spirit Blade, Spirit Trap, and Reshuffle as a couple extra spells (Spirits can be changed to Elementals if you are Fire, Ice, or Storm). You will end up with all of these if you do all of Zeke's quests through WC to DS, and reach level 50. Hope this helped you out. :)
Ice to Tower Shield (which you've done), Life to Satyr (which you've also done), All of the Sun School spells (only the ones that improve damage, you can skip the accuracy ones!), Conviction from Diego (if you're a PvP Sergeant or higher), Vengeance from one of the Star School trainers (I don't know where this one is).
You might want to pick up the Treant Polymorph too, polymorphing is very fun and the Treant does have some very useful healing spells when your health orb is about to crack!