Death magic is probably my advice with a necro, the reason being the spells do loads of damage and some/most regenerate your health upon hitting targets. Minions are fun but they die pretty quick and when running across a level from battle to battle it can take too long though they're useful for tying up large contingents of charr/enemies especially if you have a monk as an ally with you because the monk will keep healing the minions whilst you keep casting death magic thus looking after yourself and providing you with a good source of bodies to keep raising replacement minions.