Even for a single dev it might be worth it to be able to check out to your normal dev workstation, your laptop, and even on a totally random pc when the need arises. It also allows you to checkup on things through the web when a pc to checkout on isn't available.
Not to say GitHub doesn't make it even more convenient, but the DIY option isn't exactly difficult either.
http://scie.nti.st/2007/11/14/hosting-git-repositories-the-e...
I set up our repo hosting using Gitosis a few years back and haven't had to think about it since. Accounts are also managed via a special repo so even that is done over git.
You could also put your collection of repositories on your Dropbox and clone from / push to there.
And creating a new git repo just takes 15 seconds:
cd /opt/git
mkdir reponame.git
cd reponame.git
git init --bare
cd ..
chown -R username:username reponame.git
The alternative is of course to run your own repo server as you said, which with git can be as simple as just a directory you can access via SSH.
(See http://stackoverflow.com/questions/1964347/mercurial-and-i-g... and http://stackoverflow.com/questions/1960799/using-gitdropbox-... )
In what implementation of the English language would that contraction make any sort of sense?