Callas tweeted on April 19: “I deleted my Dropbox account. It turns out that they lied and don’t actually encrypt your files and will hand them over to anyone who asks.”
That's actually a lie too. Dropbox does encrypt your files, it's just that, naturally, they hold the key. If I ask Dropbox for another users files, guess what? They don't hand them over.
If your info is really that sensitive then for heavens sake don't outsource encryption and key management to a third party you have no supervision over. Encrypt your super sensitive files with Truecrypt and then share/sync them with Dropbox.