TMI - How much is too much?

I've got a question I need answering. How much is too much? Particularly in a relationship, how much do you tell your significant other about yourself?

My best friend has often accused me of saying too much about myself to the person I'm in a relationship with. I think that we ought to be honest with people about our past so that later on in the future we don't have any nasty surprises.

So, when you're delving into a new relationship, how much of yourself do you reveal?

Quote: If you dwell too much on the past you'll bankrupt the future