User blog comment:Mr Stickman/Q&A Returns/@comment-4715168-20130405201717/@comment-4470623-20130407221417

Not taking into account the damage per second, the best base damage staff is the Staff of Incineration, which does about 60 damage on impact, not to mention the additional damage it does due to the target being on fire. However, the Wabbajack has the capability to turn even the most fearsome foe into a chicken which takes only one hit to kill. So the Wabbajack could be considered the best damage staff, though not really as it also changes the gear that the enemy has. Taking damage per second into account, the Dragon Priest Staff, Wall of Fire, does 50 points of damage per second when sprayed on the ground.