For me, the one who was the most inspirational, is Pein (Nagato/Yahiko).
Why? Because he adresses matters/questions that haven't been answered not even today. With the whole hatred circle, the whole war stuff and so on.
I mean, look around you, there's still war in real life, hatred still goes on but for what? What are they fighting for... But as Pein himself stated "...No matter how pathetic the reason, it's enough to start a war. War will never cease to exist…"
Of course, in Naruto, being a fictional story, everything is going to be ok but in real life I wonder, when everything is going to be like that? When will war cease to exist so everyone will be just enjoying life?