Very nice capture Robert.
As others have said stick to the standard ISO settings, also I wouldn't recommend going higher than ISO800.
At most ISO1600 if your really have to, depending on the object.
The 40D is a great camera and it's (14 bit) sensitivity is a real bonus over the older models.
Another thing to watch out for is when using NR programs that you don't go overboard with the NR, I've seen many images with the dreaded 'plastic' look because people have applied too much NR.
Doug did a very nice job on yours.