Flying Pete, I tried to photograph Orion's sword the one clear night we had, my first ever attempt at photographing the stars, and what I captured was nothing like what you did. Was there anything else that you did, either during capture or processing? What is DPP? I have CS3 and always use that for processing my portrait photography, but do not know if astrophotography requires a different processing program.
I also have a 40D, but I don't have as fast a lens, my 80-200mm lens gives me a 4.5 at best, about a 2 stop difference. So in order to keep a 5 second exposure I could bump up my ISO to 1600. I will give that a try the next time there are some clear skies and hope to have something of a little more identifiable nebula.
DPP is the Canon RAW software - Digital Photo Professional, that is pretty much I used. I did apply Noise Reduction as I have a few hot pixels that start to show up over 2 seconds or so. I have bumped the sharpness and saturation, whilst reducing contrast.
Also I had the camera mounted to a telescope with a motorised mount which was compensating for star movement.