Best: Super Saiyan. There's a reason why most anime power-ups even now nearly 35 years later still use this form as a sort of blueprint. Everything about it was just so perfect and perfectly timed. The environment, the build-up, the OST, it was genuinely one of the best that Shounen itself has to offer. I chuckle often when people wonder what made DBZ so immensely successful. The answer is literally in plain sight, there is no "trick" here, it genuinely created action sequences that were really just that good.
