I’ve been using Dropbox for almost two years now, and despite persistent difficulties and worries with security and privacy, it’s been a rock-solid product that it absolutely necessary to my personal workflow. In addition to providing set-it-and-forget-it backup (useful for all sorts of things), it syncs instantly and even offers basic web access to your files. I had tried SecretSync, an application with considerable promise, but found that despite offering much enhanced security to your Dropbox store, it is still far too flaky to use for critical data.
Earlier today I moved everything out of my SecretSync store into Dropbox, taking that leap (eyes closed!) into the world of personal and sensitive data in the cloud.
If you want to sign up with my promo code I get free space (maybe you do too?). At the very least, use my code.