It's silly to want this I know but...
I've now had 3 major stints playing on this great site. And every time at first it didn't bother me but then I grow increasing frustrated at the one game lag in the graph.
The graph is there because it is interesting to see how the yours and others rating goes up and down over time but every time you have a big win (or loss) and look at the graph to see the affect it isn't there - that is until you finish anther game.
It is probably right that each bar represents the rating of that game before the end of the game, so why not have an extra bar with no game details yet attached so you get an immediate visual display of the new rating.