It is one of my biggest fears that I will lose my passport when traveling! I also keep the passport informational service card separately, so at least I'll have the passport number. Additionally, I scanned a copy of my passport and e-mailed it to myself so at least I would be able to bring up a copy and not worry about having to carry it with me.
My home in Aruba, Casa Koyari, my second home, Casa Del Mar, followed by Arashi and Baby Beaches!
Take a photo of your passport and put on a password-protected flash drive that you carry with you. I also take photos of all my credit cards front and back. That way, if I lose wallet, I have alll the numbers readily available plus it beats typing all that stuff up and carrying a paper copy that could get into the wrong hands. Its a great little thing to have on you when you're in European cities known for pickpockets (Barcelona comes to mind). You get picked, go to nearest internet cafe and poof, you're ready.