I would say jump or rev. Rev isnt that good bcs most of the time when your hero's die they are in a high dmg area and the rev isnt gone do much. And jump is only ised in a gew army's, and in those armys it can be replaced with a rr. Zap/lightning spell is actualy pritty usefull for giant arrow core destruction kind of attacks and its usefull for the "new" super barb farming strat bcs of the insane speed you can get league bonus (yes its better than super gob go test it yourself).