Marc, you are right about my approach to sports shooting. I don't usually shoot long continuous bursts. However, I may shoot a number of 3- to 7-shot bursts in rapid succession as the play unfolds, especially in sports where the action is continuous, such as lax or soccer. Those, too, can fill the buffer.
That said, most of my sports is shot in JPEG these days, and because of that the D7000 buffer hasn't really been a problem. I resort to raw only when I'm in a situation where exposure or color balance is iffy. But those tend to be low-light situations where I'm shooting the D3 exclusively or primarily, anyway.
I do shoot other things besides sports, though, and there have been a few occasions shooting wildlife when I've strained at the leash that the buffer imposes just enough to appreciate how frustrating it would be to have to deal with it all the time. (That's true of my D3 as well, which also has a smallish buffer.) I'm thinking of situations such as the long, low takeoffs of trumpeter swans. It's useful to be able to shoot a burst of 5-plus seconds to follow a pair of birds as they fly together, hoping to capture moments when their wings are the the same angle for that "in sync" shot. And there are many, many other examples in wildlife shooting where you want bursts longer than I, at least, need for sports. (Airshows are another subject where I find long bursts sometimes useful, although I tend to use a slower frame rate for those.)
For me, personally, though, this is mostly an intellectual exercise. The more I understand about these devices the more I'll be able to wring out of them when I do approach their limits, even if it's only rarely.