I was using Dropbox (there is not enough free space for me), Sugarsync (same like Dropbox, and for me slow).

Now I am using new service - Copy. They will give you 15GB for free.

If you register on Copy by this link, and install their application to backup / sync your data, you will get 20GB for free!
Here is the link: https://copy.com?r=zPku0e

Bonus for you is, that if you will find some referral, you will get next 5GB for free per each! Like this, you can get unlimited space for free!