As much as I love my PDA, I don't trust it. Especially when it comes to storing important data. Literally I had foam at the mouth the last time my PDA failed on me (it deleted all data in RAM, including datebook and contacts).
The problem is I don't trust my PC either. Nor do I trust optical media. Can you imagine to live with the constant fear of losing data? HORRIBLE!
But what can we do... we're all little computer people living in a digital world, right?