AL-FAMOUS said:can believe moxie recommended the d70 for this, i would say a 20D would suit you really well, mainly because you get low noise images at iso1600 (totally usable) giving you a ton of flexibility in low light situations, i would be worried about going over 400 on the D70 (not being biased, just i wouldn't feel i could get reasonable images) the 20d also shoots 5frames per second, the d70 (no matter how much a nikonian will tell you) doesn't stand up to the 20D
moxie made a good call on the sigma though - i almost got it myself but i managed to get a great price on a brand new L series lens which is fantastic sharpness and optical quality (its not just about sharpness, it about colour and contrast also) but the sigma at 2.8 is a good lens
the 20D+70-200 2.8+1.4x extender will do you a treat
$999 for D70 kit + $699 for Sigma is considerable less than the 20d + kit lens, which isn't as nice as the D70 kit lens. Then they'll have 28-300 equiv covered versus 28-80 on the Canon side.
The canon 20d also doesn't shoot 5fps, but is rather ADVERTISED as 5fps. Alot of people's independant tests show it's 4.5fps for the first burst, and slows down until buffer is filled. D70 shoots much more consistently at 3fps.
In my mind, fps is one thing, having to stop and take out the film is another. Waiting for the buffer to clear is the digital equivalent.
The d70, at its price, is a much better starter sports cam for someone. And let's be honest here. The d70 isn't bad at ISO 200-800. It's useable at 1600. You're obviously programmed by canon to believe that noise is such a huge factor. That said, a D70 is gonna be less noisey that it's film equivalents, and even much more so than any other p&s digicam.
Maybe at 1600 & 3200 the canon wins. But at the price point, they don't have enough for the sigma lens. So they're stuck without a good telephoto. They have to crop, and there goes any resolution benefit from the 20d.
If you're serious about recommending the sigma, don't bust their budget on a body!
And let's lastly make this clear: a D70 with nikon's kit lens should run circles around a 20d with it's kits lens. Apples to Apples (or as close as possible) and we can see that EVEN at $999 the D70's image is gonna be rendered much better because the glass is better.
The measurebators (low noise ISO and high mp people) like to keep bringing up noise issues and whatnot. Getting good glass can cut 20-30% of the noise from a shot. I used a crappy lens on my d2h for an ISO 1600 shot. It sucked. I swapped out that lens and put on my 35mm prime, which is a BRILLIANT lens, and took a similar shot and the results were HUGE. Glass is almost everything in photography. And much more crucial to mp and ISO. Good glass begets good images.
Put a 24-70L on your 20d, and we'll talk. But I could then just go and put a 17-55 on a D70. And even then.... the D70 comes out cheaper.
You'll replace your digicam in a year or two. You'll keep that 70-200 Sigma much much longer. Get the d70, save some cash on your body purchase for a good tele lens, and you'll be much happier and get much more bang for the buck.
And don't worry about ISO noise on the D70. If you take some time and learn how things work on it, you'll get similar results to the Canon. And remember this: noise in prints doesn't really start to show until you're at big enlargements. If you're going for 24x36... maybe a 20d. If you're gonna be printing at 8x10 or smaller, do yourself a favor and invest more $$ in good lenses.