If you want to play a pk based mage the best thing for it that I've ever played is Outlander Air/Offense. Within 3 minutes of logging in you will know where all of your enemies are if they aren't under water or in the underdark (for the most part). Flying to anyone unprepared with an offensive form 60% of the time will result in their death with forms with any sort of lag. Being outlander means you don't have to worry about movement while flying, and that is huge. The other powers are nice as well.