Matt Laur , Apr 06, 2012; 11:02 p.m.
Nikon isn't trying to sell you a D800 for sports. The new D4 is their flagship sports camera. But it's even more expensive. Depending on the types of sports and the venues in which you intend to shoot, you'd do great with a D300S, or with whatever they (shortly, I'm guessing) replace it with.
But the killer part is lenses. What sort of sports and shooting circumstances/access do you envision? That dictates the glass.