You *need* a dSLR to do sports shots. I have a S95 and a G-series. It's just not doable. I'll take my T1i anyday even if its just a 55-250 and the camera is slow as hell at framerate.
There's something about using a VF to AF and track a subject in sports and fast motion that's just WAY more satisfying. I use the viewfinder in my g-series and I find my results to beat my S95 anyday.
While the D70 is a good deal, I'm not too familiar with Nikon. I find that like recommending a 20D or 30D.
Several reasons why I shy away from older models:
- Smaller LCD screen (you're not shooting with it, but still its nice to look back at images)
- Low resolution LCD (problem when you look back. My friend's XSi vs my T1i is exactly the case. You can easily tell AF issues from my screen rather than waiting to upload to a computer and then judging if your camera focused properly or not)
- Better noise reduction - Newer image processing.
- Better sensors/higher resolution - While higher resolution is not necessarily better, noise reduction has always followed MP count, so most of the time even while you bump resolution, your sensor is of better quality that it makes up for the blowing up of pixels. Some cases where 40D vs 50D you could say the 40D is better in IQ/noise, but the 50D can hold its own for the most part.
I know people recommended the 40D for a long time on Nikon because its a budget camera, but the newer cameras have way better AF points (more too), and while the 6MP sensor was amazing, the fact that I can crop the hell out of my 15MP shots and still retain great detail is a plus. I guess part of the problem was the D3000 sucked, but the 3100 brings back a great image sensor.
Anyway, I digress.