The most consistently powerful skill over the entire history of D2. It has to be frozen orb. It was totally awesome all the way back in day 1. It's never been nerfed other than adding a timer to it. It's always been a powerhouse that can hit everything on the screen. Zeal used hit 20 targets, and if could be interupted, making you miss for the rest of the zeal. Fanat used to only add speed. Skeletons used to be really weak, and you couldn't walk through them. Bows used to all do horrible damage. Javs used to only come in white. Lots of skills became useable with the creation of synergies in 1.10. Lots of skills did more damage in 1.08 than in 1.06. The only skill that can come close is whirlwind. It's been nerfed about 4 times, but it's still quite good. It doesn't spray slowing, resisting piercing ice bolts everywhere on the screen though.