I have for about a year now done all my work out of Dropbox (via a symlink from ~/src) it works great for multiple machines and has added advantages, eg. I never worry about deleting files that aren't staged anymore, as I can undo the delete from Dropbox’s website.

Git is for long-term version control, working out of Dropbox is like having a script running that stashes and unstashes every change you make so that its in the git-reflog.