TBH, did a shoot yesterday in the pouring rain so thought I'd shoot raw + JPG to give me processing options, especially with available light being so poor and having to work quickly with flash due to the rain.
In terms of the JPEGS, I'm happy (on the whole) with the results and they give me a starting point for minor tweaks in LR3. The old D2x has done a good job on the WB front and saturation and tonal range is good. Mind you, I was always going to be mindful of nailing exposure shooting at ISO 800+, so it wasn't like shooting blind. The only duffers were the ones I expected; shooting into a massive highlight (the lake surface) so effectively backlighting the subject. Plus, doing the catch shots as the light was going at 3pm was a bit of a pain because of the guy wearing a cap (eyes in shadow) but showing off small bream (very reflective), a nightmare when you want to pump flash in but not overcook things.
IMO, had I shot earlier in the day there wouldn't have been any problem - I'd have happily processed the JPEG file to get a good balance between highlight and shadow without any problems - but because of conditions deteriorating so rapidly, the end shot wasn't great, which I could tell instantly from the LCD and histogram. To me, that's where the raw file is coming in a big help because I can recover those highlights pretty effectively without overegging the shadows and giving the guy the eyes of a junkie!! No argument from me there on the effectiveness of raw capture.
On the flipside, I did a shoot on Tuesday in North Yorkshire and it was blue skies and warm sunlight - perfect after the crappy winter we've had. Again, I shot raw + JPG but to be honest, on some shots, the raw file gives me no advantage whatsoever over the JPEG (when processed through LR3), other than being able to work on it in future without any in-camera alterations already in place.
My conclusion is yet to be formulated about this whole debate but nonetheless, it's at least enjoyable learning about how people approach their photography.