I use Dropbox. Any files that you drop into a specific folder are automatically synced to all other computers linked to your account. uploads and downloads are also very fast. Downloading my entire account (about 2GB) took only a few hours, and uploads are similarly fast. Really good if you need files on multiple computers to always be updated with the latest versions. Also even the free versioni of dropbox will keep all revisions of all files for 30 days, so if you accidentally delete everything in a file and save it, you can re-download a previous version. I have over 200 versions of my source code that I can roll back to lol.
Pricing for dropbox is 2GB for free (with easy opportunities for up to 3GB more). 50GB for $5/month, and 100GB for $10/month.
Absolutely stay away from Mozy. I tried their free trial and after 3 weeks it still hadn't uploaded everything that I told it too. If you do lose everything it would take forever to get it all back. If you plan on backing up all of your data, definitely go for carbonite though.
Anyway if you do go for dropbox, PM me for my referral code so I can get 256MB more storage