Over the years I've brought my parents closer, been a positive influence on various people and my wonderful ex-partner, from whom I was ripped by my abusive and nasty ex, has said that I completely changed her life for the better. So much as I don't value my own life, whether or not I would be willing to deprive those I have loved and cherished over the years of their memories of me, and deprive the world of the good I'm told I've brought to it (which admittedly, I do not see myself), that is a very difficult question.
Would the lives of everybody who has met me and has memories of me, ultimately be better if they'd not met me? If so then the utilitarian in me dictates that I would indeed press the button and retrospectively destroy any trace of my existence. But if those I love and care about were to suffer or be deprived as a result of me never having existed then as much as it pains me to stay here, I couldn't bring myself to push the button.