The RasenShuriken... i love throwing shit for some reason and i love the idea of a jutsu that could completely annihilate someone from within on a cellular lvl and at the same time look like an explosion... imagine if a diff affinity could be added to it or would be added to it cuz i'm sure it's possible like fire... i dunno maybe naruto could combine the TBB with wind and create a TBB RasenShuriken... totallly badass...
Actually my real favorite is Jiraiya's Senpou: Goemon:
This technique is so awesome, it would literally had reduced Pein to nothing, this technique is highly difficult to avoid and he is hell of a jutsu, plus well if it counts my favorite Mode is Sage Mode!