If I see that correctly, you mean by missing shots, that you would like to make more shots per second right?
Then I think you need a camera with that feature, speaking: a D300.
A better lens gives you more AF speed, meaning your lens will focus faster (wich will probably happen with a new body as well, even more with e good lens).
Could it be, that you have - on you D80 - the time exposure on? I don't know what the English name in the menu, but it optimizes the noise performance of the camera when doing time exposures. If that feature is off, you will have more pics per sec.
My advice: good to a good retailer, take your D80 + new lens and try it out, then a D300 + 55-200, and then D300 + new lens... whatever suits you more.
Sorry, can't help you more, I'm far from a specialist. You might want to ask other people, unfortunately there is not much going on in this forum, nothing really, pitty.
Cheers
Mike