The short version of our results: I don't care which option you use, just
back up! Now! Seriously though, it's interesting to see Dropbox as a backup
solution. Yes, it does versioning, but I guess I've never considered it a
backup. Perhaps I'm too old.
*Popular write-ins: BackupPC, Deja Dup, SpiderOak, duplicity and rsync + tar/btrfs/ftp/cron/and so