For my first game of Dragon Age Origins I'm playing a mage. So far I've concentrated exclusively on dealing two types of damage so I can get to the higher level spells faster. Right now fire is my primary and acid (is this Earth?) is my secondary. However, I'm worried that I'll encounter opponents resistant to both types which will neuter the effectiveness of my mage.
What damage types will best carry me through the game?
(Let me just say that getting my first really good AOE magic attack, fireball, has catapulted my mage from dealing about 1/10 of party damage to dealing >1/2 of party damage)