Well obviously no one knows... or very few people know (I still think that there are a couple original bitcoiners on this forum who are 99% sure that they know who Satoshi is).
Whats your favourite theory?
Mine is that it was John Nash

Please provide some proof for your theories. Would love to look into them!
I think this guy is not real or not exist at all because his identity and where about is still uncertain that even the Japanese did not see this guy so i believed that this is just a name in order to create a history of Bitcoin in which the real creator of Bitcoin and the block chain will not be known by everyone. If Bill Gates and Warren Buffett are known billionaires by everyone in this world then there is no reason that security is the reason on why this Satoshi guy is not revealing himself.