I guess I just don't get the whole AF thing. There is no way I could select an AF point while tracking a moving subject (well maybe a sleepy turtle) before the shot is long gone. If I let the camera pick a point, it generally picks one that is furthest from intended subject.
In the days of manual focus, I simply used the ground glass for moving subjects, or prefocused, or used hyperfocal settings or all of the above. With today's reduced viewfinder space and lenses that are not intended for manual focus, trying to focus manually on moving subjects ain't all that easy.
The only "solution" I have for the moment is to use the single center point for focus all the time. It also has the advantage of being where the spot meter is. A half press does the focus/meter thing, recompose as needed and shoot. There is more than enough complexity in that scenario to keep me busy and to reduce the keeper rate. If the shot is static enough for me to mess around with selecting AF points then my method works as well and is faster.
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Auto-area AF works very well for quick draw shots, with the camera giving preference to closest subject -- but closest subject is not always the best, which is where more nuanced configurations come into play. The main caveat to using too many AF sensors is that it can slow down the camera's acquisition; and that, in addition to not always wanting the closest subject prioritized, is why using Auto-area AF is not a panacea to all AF situations.
There are 15 sensors on the D300 which are all equally capable; unfortunately they are all grouped into the center 3x5 portion of the available 51 sensors. However, the surrounding AF sensors do fine under daylight conditions and are reasonably good in less than ideal light.
As I have already written here, by setting the camera to 11 Point AF Selection you can quickly select one of the 11 AF sensors displayed in the viewfinder. My thumb moves effortlessly between the AF-ON button (which I use exclusively for focusing) and the Multi-selector button, and I have no trouble selecting and then tracking birds in flight using this technique.
On Nikon DSLRs the spot meter is under whichever AF sensor has been selected, so that is not a consideration.
The problem with traditional "focus and recompose" using AF-S is that the actual focus distance changes after the camera has locked focus. By using 51 point 3D Tracking and AF-C instead, the focus adjusts as you recompose and you get more accurately focused shots.
I pretty much never use Single point AF on my D300. For me it is always useful to use 9 or 21 points Dynamic-area AF tracking to give the camera a chance to maintain precise focus even when the originally acquired target has drifted off of the original AF sensor. With all the configurable function buttons available on the D300, I have one set to quickly change Dynamic-area AF modes so I can dial in 9, 21 or 51 point 3D tracking in about two seconds -- this is not a big issue for me as I tend to stay in one of these tracking modes as long as I'm shooting a particular subject.
If your "keeper" rate is less than 98%, then you are shooting extremely challenging subjects and/or not fully understanding and utilizing the D300's capabilities.
