I use a number of cloud storage services – some paid and some free. Seafile is probably my favourite as it includes server-side encryption.
I have just come across copy.com from Barracuda. This gives a huge 15GB storage for free, which is very reasonable. If you use my referrer link, we’ll both get an extra 5GB, so you can start with 20GB. I have five referrer opportunities using this link.
Update Mar 16: service is being discontinued from May 16. Shame.