I use a variant of the Martini Method where I try for at least 2 substantive svn commits a day (not including minor bugfixes or cosmetic issues). I try to do atomic commits, so this correlates very closely with function points. It seems to work quite well; since the beginning of the year I've gone from r569 to r623. It's had a corresponding effect on observed product quality, having gone from essentially a blank webpage to the full editor skeleton, a working game, and several widgets for customizing it.