Arcane is better dps when you aren't geared. They just buffed it last patch, less mana used, more likely to proc missile barrage. My mage is geared, and dual spec Arcane/fire, fire uses less mana than arcane in my experience. Just make a quick macro for 4 arcane blasts and an arcane missiles, and you are good to go. Make sure u use Mage armor, combined with talents you get 100% mana regen while casting, which helps a lot for arcane mages.