So a lot of investigations have been done on this subjects. But everything I read about Nakomoto, are just a lot of guesses and a few intelligent suspicions.
Just a short recap:
Nick Szabo creator of bitgold, precursor to Bitcoin. A journalist linked him to bitcoin using stylometric(written style of language) analysis.
Dorian Nakamoto (birth name Satoshi Nakamoto) systems engineer who worked on classified defense projects and computer engineer for financial services companies. He was laid of and turned libertarian. Also satoshi's P2P pseudonym posted the first time after 5 years of silence that he is not Dorian. (really interesting)
Hal Finney his writing had the closest resemblance to Satoshi's writing; Satoshi made the first bitcoin transaction ever to Hal Feney. Hal also worked on the software and made improvements.
Craig Steven Wright Self proclaimed Satoshi. Australian. Probably an intelligent scam.
Michael Clear A young c++ programmer. Cryptography graduate, worked for an Irish Bank to improve its currency trading software. P2P knowledge. Denied claims that he was Satoshi and suggeste Vili as the possible creator of BTC.
Vili Lehdonvirta Finnish programmer, creator of video games and virtual currency student.
My wild guess
We know that Satoshi had a deep knowledge of C++, and deep understanding of P2P networking, Cryptography and Economics(Dan Kaminski). He also has a researcher/PHD style of writing(BTC whitepaper).
Also we know that he used British English occasionally in Code commenting and forum posting. Used perfect English.
We also know he had no online activity between 5 a.m. and 11 a.m GMT (Stefan Thomas graphed the timestamps on Satoshi's posts.)
Dennis Ritchie
Creator of C prgramming language, key developer of Unix. Died in Oct. 2011. He had deep knowledge/understanding of programming languages, operating systems and I assume security and cryptography as well. I am not sure about his knowledge in Economics but still he a person to take in consideration. What if he wanted to make a gift to humanity. He was ill in his last years. He also live in Berkeley Heights, New York, matching the location of posts. Also Satoshi said he was moving to something else.(weird)
Bjarne Stroustrup
Creator of C++ -> deep knowledge of C++. Working for Morgan Stanley as a Managing Director -> Economics knowledge. I bet he has understanding of cryptography(really needed in banks, for their trading software) and probably P2P networking too. As for his reasons as a possible BTC creator, I don't know. Maybe he is secretly a libertarian who know, maybe one of the reason he didn't want to come public is his connection to Banking and how it would be misinterpreted. Or maybe it really is a secret corporate project afterall(in order to support this claim see Dan Kaminski's thought on BTC and why will be centralized in the future).
A Team of highly intelligent people
Maybe it was a team work between some of these guys. Or maybe it was a secret project commissioned by banks or corporations or government or some other organization like CICADA 3301(which were searching people with strong knowledge
of cryptography, data security and stenography )