Carbonite wants to install a small, nonintrusive program that scans for changes to files. Not keen on that and I bet it doesn't play nicely with linux.
I've used dropbox occasionally, (very) simple interface and 2gb is free. I believe it's based on rsync, though I may well be wrong there. It offers 50gb for $10 or 100gb for $20 per month.
Alternatively leaving hard drives dotted around works well. I've got a flash drive at a friends with my work documents on, but haven't organised offsite backup for anything else.