Quote Originally Posted by Firo Volondé View Post
Considering how, without his wand, Voldemort is as strong as an average human (probably weaker than average, as he doesn't have much need for physical strength), I'd have to say Orochimaru. His Horcruxes do nothing but prevent death, and would not protect him from being beaten to a bloody pulp.
Technically wizards in the Harry Potter books can use magic without their wands, it's just less focused that it is with a wand.
But there is, of course, the problem pointed out already that the instant-kill spell would have to hit. Usually when a ninja in Naruto gets hit by something it's either a clone or a replacement technique.

Orochimaru would win hands down just because of his speed; wizards in the Harry Potter series seem to just rely on magic, so they probably aren't physically capable of dodging anything that a ninja like Orochimaru could throw at them (particularly after dying a couple of times). The only conditions by which Voldemort would be likely to win is if he had either a time freezing spell or a second basilisk up his sleeve.

Voldemort has the ability to speak to and command snakes. My bet says that if they ever crossed paths they would probably strike a deal and team up.