What is the most interesting line we should begin with, while giving an autobiography speech?

There is no single best line or standard format for the opening line of an autobiography.  As with any speech, the opening should grab the attention of the audience and draw them into your story.  Your opener will depend heavily on the tone of your speech.  Is it humorous? Serious? Dramatic?  Once you have decided the tone of your speech, you can begin to devise an opening line.

One common quality among great opening lines is that they...

There is no single best line or standard format for the opening line of an autobiography.  As with any speech, the opening should grab the attention of the audience and draw them into your story.  Your opener will depend heavily on the tone of your speech.  Is it humorous? Serious? Dramatic?  Once you have decided the tone of your speech, you can begin to devise an opening line.

One common quality among great opening lines is that they leave the recipient wanting more, sometimes by introducing a cliffhanger.  A cliffhanger is simply a situation or line that provides or hints at conflict without giving the resolution to it.  This introduces an internal conflict in the listeners that most people want to settle for themselves by finding out the rest of the story. 

A humorous opener will often challenge the audiences notion of what they are about to hear.  It does not have to be readily apparent to the audience what the challenging line means, so long as it is quickly explained.

• "The sky was a blinding white, someone was screaming, and I was cold and naked.  I had just been born." 

• "Most people call me Jim, mainly because that's my name." (paraphrase from Blazing Saddles)

One of my personal favorites is the opening line to The Catcher in the Rye (J.D. Salinger, 1951).  It is a work of fiction, but written in an autobiography format, narrated by Holden Caulfield.

"If you really want to hear about it, the first thing you'll probably want to know is where I was born, and what my lousy childhood was like, and how my parents were occupied and all before they had me, and all that David Copperfield kind of crap, but I don't feel like going into it, if you want to know the truth."

Dramatic introductions depend more on a cliffhanger to get the audience engaged.  They can be simple or complex, each work equally well.  Moby Dick (H. Melville, 1851) is a great example of a simple dramatic introduction; "Call me Ishmael."  The beauty of the sentence is it practically demands the reader to investigate further, almost as a challenge.  Richard Nixon used something similar in his autobiography RN: The Memoirs of Richard Nixon, "I was born in a house my father built".

There are many ways to begin your story, and only you can determine the most interesting part of your life to tell and the tone it calls out for.