This all depends on wheather you plan on soloing alot or grouping.
For solo, necro's are pve gods, matched only by botted minstrils and juggy/ml9 cabbies. Sorcs are also a good choice, though the pet does steal xp based on how much damage it does to the target.
In group work, get yourself an ice wizzie while you are leveling up- you shouln't have trouble in an activly leveling alliance since with tanks to guard you you can basically power level yourself. They are also extremely useful in lords room defenses, though waiting on that isn't as fun or sexy as a fire or earth wizzy bolting folks from the ramparts.