pgt: How about a system along the lines (counting for action points or not - you decide)
When the game is over you win a number of points that equals the number of moves divided by the sum of all the time it took for you to make each move in that game (maybe take out a couple of the slowest moves to balance things when you go on vacations and such).
It would give you a "moves per hour" type of statistic that, if published seperatly, could help others choose between slow and fast moving players as well. It wouldn't also matter weather you have many open games or not - your overall "moves per hour" rating would be more established if based on 10000 games, but would be just as meaningful if only based on a couple of games per month.
Of course, it it added up to the action points, the more games you finished, the more points you'd win ;)