I think you go too far. Organizing all my data is one thing. Google Desktop's new feature of collecting every piece of information about me and that I own and transferring it to your site (in order to make it globally searchable) is quite another. Regardless of the integrity of your security, your well-intentions, and your vow to do no evil I have the following concerns.
1. Security is fleeting; it only takes a single exploit now or in the future for a malicious cracker to steal all my information from you.
2. Corporate policies change; corporations have no morals and no goals other than to maximize shareholder value and cannot be punished for wrongdoing.
I would not grant any other company the level of trust that you ask of your users. Therefore, despite the fact that I believe, for the moment, in your intention to do no evil, I cannot justify granting you that level of trust either.