I just got a D40 as an early Xmas present. I'm new to photography in general (was using an old crappy point&shoot digital before), but I'm liking it a lot.
Here's a pic of my favorite hermit. I used manual settings (didn't know how to adjust aperture at the time since I'd only had the camera a few days, so it's pretty much just manual focus), so most pics are not in focus. He's right against the glass. The lens is the 18-55mm that comes with the camera.
(click for the full size pic)
Obviously, I haven't owned any of the other cameras on your list, so I can't really compare. Good luck with the decision!