I'm a big fan of atomic committing. "Commit early and commit often," was one of my first lessons I was taught while learning gitiquette. It tends to be a point of contention sometimes when developers get into the nitty gritty of what constitutes enough of a change for a commit, but I personally have always felt like you can never have too many commits. (As long as you write good messages. Without those you're gonna have a bad time.)