Understand that the Internet is a completely new medium. The copy that pulled high response rates in the world of direct postal marketing doesn't get read on the Net. Especially not as email. The subject is the headline. Your subject determines whether your email gets read or not.
Internet users are smart and they know exactly what they want.
They resent being tricked. It's a tough way to start a relationship. Make it personal. People on the Internet want personal notes. Write for an audience of one.