Will the police do anything about it?
Of course they will. I guarantee that if you go to the police and tell them you've had a large amount of money stolen from you, they will, in fact, do something. They have identity theft and fraud departments specifically trained to handle these sorts of cases. They won't necessarily be able to get your money back, but they'll sure as Hell try. Why people here seem to think the cops won't do anything is anyone's guess.
I called the San Francisco police department to discuss reporting a case. The officer to whom I spoke was polite and admitted knowing nothing about bitcoin. He mentioned that the SFPD does not have a cyber crimes division and that it would be highly unlikely that any sort of investigation would actually take place, which was not a surprise.
He did say that if I wrote a summary of what happened and provided documentation, it would be added to the police report, and that about a week after filing I would be able to get a copy of it to submit to Mt. Gox.
My next step will be to write up a summary of the events and go to a police station to file a report.