Who do you think has the best defence in the Narutoverse?

[Joki]

Well going by physical defense here and not intangibility or any of that stuff..easily the Susano'o users. Although they're far from unbreakable and have weaknesses moderately easy to exploit.

Gaara would have a better "all around" defense though it's still much weaker in comparison than Susano'o(specifically full tengu armor here)

 

[Ngylle]

susano

 

[House]

Nagato. No need to say anything else.