I absolutely love DropBox and use it to sync my laptops, home and work computers. One great use for it, I think, is Tomboy Notes, which I use to take notes in meetings on my netbook, track progress on projects at work, keep a list of stuff I need to do, etc. I don't really use it for source code, which is usually version controlled anyway.

> What do you all think would happen if DropBox went out of business. Would they make sure we all had copies of our data?

That's the beauty of DropBox; you already have copies of your data, on all computers that you sync to. It's really convenient, especially on laptops that aren't always connected to the internet, etc.