Although this might be slightly off-topic (in a discussion about focusing), I thought it might be useful to point to this D300 Custom Settings Spreadsheet at Nikonians.org. The author explains:
I’ve tried to be thoughtful about the settings I have chosen to illustrate these modes, but the ultimate purpose of the spreadsheet is to help you to learn the camera and to make it your own. Please take these settings only as a starting point to help you personalize the camera so that it reflects how you use it. They are there to get you started using some of the amazing capabilities of the D300.I think that having a whole range of example settings can make it much easier to choose one's own.