[anusinha]

One possible answer is to use encryption of some sort when uploading/downloading files. This is annoying to implement though.

[seagreen]

I highly recommend EncFS. It's easy to set up and simple to use. The main downside I know of is that is doesn't keep the number of files or their sizes private but, really, who cares?

[qu4z-2]

I've recently stumbled across tarsnap. It's command-line, but if you're not afraid of that, it's very nice.