This has been a fascinating discussion. Thanks to all for taking the time to work on the image and share your results. In particular, I'd single out MrGuy's very detailed post with side by side comparisons of several different ways to approach the image but it is all very useful.
I decided it was time for me to chip in again. Below, you can see the original JPEG and what I have just produced with a couple of minutes working on it:
That is similar to some of the examples above and not so much to others but captures a final image that I am happy with, stuck somewhere between what I saw and the picture that impressed itself on my mind (I'm aiming for a graphically strong effect as much as for "realism").
To be honest, I'm still not convinced that I want to step beyond my habit of shooting in JPEG mode at the moment. I can easily get results I am very satisfied with and I don't think I have the time to push that little bit harder on any given image. I rarely view my images at full size (I was suprised how blurry this one was when I worked on it this morning... that's what trying to handhold a 90mm lens at 1/60s on an overcast day will get you!) and suspect not many other people do either. My taste is for quite intense shadows and highlights and I can generally get a suitable exposure for those in-camera without requiring the "digital negative" of the RAW file.
It is also partly due to the system I mainly process pictures on - a wonderful little Mac Mini. I think it is a great machine but it only has 1GB of memory. On a beefier machine, operations like RAW processing might not taking appreciably longer but they do with my Mac. If I had plans to make my photography pay for itself, I would probably figure in upgrades to my set up which would reduce that time cost.
Wulf