Well, I voted Neji just because he's so cool and using chakra seems to be alot more flexible than using sand or spider-armor. It doesn't weigh anything and lets you move around.

But everyone who has said running is right, the only absolute defense is either running or never getting into a fight at all.

Plus, defence isn't everything: you can have a truly, utterly unbreakable absolute defence, and if you don't have an equally strong offense you won't win a fight.