Up to now, I was mainly relying on hard drive backup: with my previous Mac I used to use a 500 Go HD connected through Firewire 400, and now I am using a Time Capsule again. Backups are done manually every two days approximately. I also have a Dropbox account but it is mainly to store in the cloud some documents I don't use often, and occasionally share papers or text files with other people. I also use Dropbox to store all Image files that appear on this "blog." I also expect it to serve as a gateway between two Mac: a Mac Mini at home, and my Airbook at work--more to say later.
Problem with local backup is that if the disk crashed or something bad happens at home (fire or whatever), everything is lost obviously. This has been discussed at length on the internet, e.g. one that I recently found Backups and the Cobbler's Children.
Yet you have to pay for that, whether you exceed your S3 free storage (5 Go) or simply for the application; $29 for Arq remains affordable, though, and I don't plan to exceed my S3 Bucket. Arq is currently uploading my data to Amazon Glacier, which according to the docs implies a 4-hour delay to get access to your data but at a reduced cost. I believe this was what we need for a simple backup of critical data that we would miss in case of total breakdown of our system.
My last Gmail cleanup is now more than one year old. (I still don't like pie charts :-) I realized that it is a waste of time and HD space to susbcribe to 10+ listservers when you could simply browse them through simple CLI.
And here how it looks under Emacs: