For the record I would like to share my technical analysis of the Satoshi email which I wrote in a pastebin (http://pastebin.com/Ct5M8fa2) a few days ago.

1. The email is the one used by Satoshi to announce Bitcoin in the first place. 
http://www.metzdowd.com/pipermail/cryptography/2008-October/014810.html

2. The email was not spoofed, it actually originated from vistomail's server. The email headers show the email originated from 190.97.163.93 and the SPF records show this as an authorised sender for the email. This does not prove the account wasn't hacked of course, or that the account might have expired and be re-registered by someone else (vistomail is a paid for email provider).

3. While the email is not signed, and there are a number of PGP keys listed on key servers for him (to vary addresses), he didnt sign any emails with any PGP keys.

It is therefore not possible to outright dismiss the email's authenticity as the email originates from an authentic source. The only questions is whether the webmail service was hacked or commandeered somehow.