I'm shopping for a 70-200 F/4 USM IS L, and took a few test shots with it. Here's a full resolution jpeg, and a 100% crop with a focus point highlighted. It was shot handheld with IS on at 70mm / F4 ...
My wife has a Canon 40D with a Sigma 17-70 DC (no image stabilizer) lens. She sometimes goes on shooting trips with a friend of hers who has a Nikon D90 and a AF NIKKOR 35mm f/2D (fixed focal) lens. ...