Oft touted on HN here is tarsnap[1] and rsync.net[2]. They both have different pricing models, and both seem to focus on security.

[1] - http://www.tarsnap.com/ [2] - http://www.rsync.net/

I looked at TarSnap and I dont quite get it. I am using Dropbox now. Do I keep my files in the same structure and manually tar them and upload? Does the tar and upload happen automatically? The site doesn't quite explain how I get my files up...What about the always in-sync features like DropBox?

This could happen to any other online file storage provider too. So depending on your needs, you're probably best off encrypting your files yourself before storing them online.

None. I'm not so hot on Dropbox right now, but they're still probably your best bet.

Just encrypt everything even remotely private in an Apple DMG or Truecrypt volume.

I tried UbuntuOne for the first time yesterday, but was awfully slow especially compared to Dropbox

Wua.la and Tarsnap

www.skyfile.co it has a easy API