Since I mentioned how much l like Dropbox in my last post, I thought I'd add a follow-up. There's been a bit of a buzz* lately about how insecure Dropbox is. I don't see this as a reason not to use it, but extra precautions should be taken if you want to store sensitive information. I personally love TrueCrypt for this, as creating a fixed-size encrypted drive doesn't leak information about the number or size of files you've encrypted.
* Derek Newton's article "Dropbox authentication: insecure by design", and Christopher Soghoian's article, "How Dropbox sacrifices user privacy for cost savings"