For my personal projects (mainly Android applications), I only had local git repositories allowing me to really develop without being afraid of losing history. However, these local repositories were not synced anywhere but on my own hard drive (that's not really a secure way of handling things). My first attempt was to do as often as I though tarballs of my repositories and sync them on Dropbox.The problem in the chain was the fact the backup were done at times, which, in practice, means really rarely.
I had looked for free git hosting providing private repositories, but I did not find a free one that satisfies my main prerequisite : unlimited (or large) private repositories count.
A few days ago, I cleaned my whole personal development folder and I began searching another time for a free hosting. I found out that Bitbucket, which at the time I first looked at it was only providing Mercurial hosting, now offers free git hosting with unlimited repositories.
The "one more thing" of this hosting solution (but not only) will only be interesting for Mac users. Atlassian released a free GUI client for Git and Mercurial SourceTree.app, and, although I am not fan of a GUI for Git, but I must say I use it regularly (its branch view is awesome).