Re your original question:
Please note that the Nikon 55-200mm f/4-5.6G ED IF AF-S DX VR ($249) is not a constant F/4. It is only F/4 at the wide end. If you zoom a little, these lenses stop down very quickly, which is why they are so inexpensive.
find a lens rental near where you live and rent one of the good lenses. I rented a Nikon 70-200 f/2.8 last spring and shot a few soccer games with my very old nikon DSLR and the images were almost all fantastic. Zoomed all the way to the tele end, the images were all razor sharp, in focus and had great colors.
Some rambling about these two lenses:
I could not believe that it was possible to get these great images from my 8 year old low end nikon body. I have borrowed other brand lenses from friends, an old Sigma 200mm zoom, and a 80-400 nikon, and nothing came even close to the image quality of the 70-200 f/2.8.
Its really tough to compare the 55-200 f/4-5.6 to the 70-200 f/2.8, since they are so far apart in price. They are not in the same ballpark. The 70-200 f/2.8 is a professional lens, its built like a tank, and the image quality is spectacular. The 55-200 is a consumer level lens, lots of plastic, and you won't get anything close to the images you can get with the more expensive lens, and its not constant aperture.
With constant f/2.8 I was able to get shots on cloudy days that were far out of range of my cheap 18-135 f 3.5-5.6 kit lens.
That said, my fingers were tingling from the weight of carrying the 70-200 f/2.8 around for a couple of hours. It is a very heavy lens, and detracts from the experience of whatever else you're trying to do (family gathering, sports event, etc).
Rent the good lens, see what the images look like, and then judge for yourself if $2099.00 is worth it to you.