Those are programs, not services. Dropbox is a great service (client + server) for syncing your files. There is no other simple option that "just works". So my

Those are programs, not services. Dropbox is a great service (client + server) for syncing your files. There is no other simple option that "just works". So my choice is Dropbox + encfs (to encrypt everything). But I also keep another local copy of the entire dropbox folder in case the sync fails and decides to delete everything.