I have a D90 and I've tried to set the Fn button on the front to display grid lines and it doesn't seem to want to work. If I press Info it shows the little gridlines box, so I'm assuming when I press (or hold) the Fn button it should show me some grid lines. No such luck. Tried it in Live View as well to see if it was some dumb LV feature, and it won't show up there either. Am I missing something?