I think you might have a slight misconception about the Nikon and autofocus. The Canon is essentially the same - autofocus is lens-dependent. If the lens doesn't have it, that's it. That said, almost all consumer lenses in production today are autofocusing lenses. The camera bodies themselves vary as to how many autofocus points are in the viewfinder, the sensitivity of each of those points and how you can choose the points, but the lenses contain the motors that actually focus the glass. As such, autofocus speed can vary depending on the lens, but even the slower autofocus lenses generally focus faster than most point-and-shoot digicams. And Nikon also has IS (they call it VR) lenses, but Canon rules the roost when it comes to the number of IS lenses available, particularly on the telephoto/super-telephoto end.
Some of the Sony's lenses are Karl Zeiss, but not all. I'd say Sony probably has the best shot of actually becoming a contender in the DSLR field simply because of it's size, but Canon and Nikon built their name on photography and are by far the dominant forces in the field.
As for me, I love my Canon 20D. Definitely try out cameras in a shop before you buy, though. I found the Rebel to be too small for my big hands, and felt the general Nikon layout wasn't as intuitive to me as the Canon one (though admittedly I've used nothing but Canons since the film days so of course I'm more comfortable with them).
