re: How to deal with an email stalker?

Report it to his e-mail provider and block him from yours.

Or ratchet it up a notch: if you know where he lives, call the PD or Sheriff's department and file charges for cyberstalking. They take it pretty seriously in most jurisdictions these days, and a third charge in a lot of jurisdictions bumps up to a felony after two prior misdemeanor convictions.

Of course, if he's threatening death or seriously bodily harm, it may already be a felony.