You've specified the zoom range of each lens but not how fast it is, which is the more important factor.. If you want to do fast stuff, very well, either get a fast lens (eg f/2.8) or a slightly slower lens (eg f/4) but with VR or IS and hope it's good enough

The 70-200 f/2.8 lens gareth is talking about is about 450-500 from hong kong, about 600 i think from warehouse express.. it'll take the best shots you've ever done.. but 200 still isnt that much for some track stuff.. it's ok for full frame shots from about 20 metres or so.