I have a 1Ds Mk ii, so probably not that relevant. I use: -
RAW (which probably reduces the impact of the following)
Noise Reduction Off
Color Matrix 1 Standard
Tone Curve Standard
But I make the occasional time lapse movie (the 1Ds cameras are great for this - built like a tank, you just leave them outside overnight and turn them off in the morning). For this I use small or medium JPEG. When I start shooting stills again, I often forget to change it back to RAW. I'm often surprised by the quality of the smaller JPEGs. Not as good as a RAW file, but still pretty good and fine for non-critical use.
FWIW, I also have an Olympus EPL-1. It makes great JPEGs in camera. I can rarely better the JPEG file by a noticeable amount by shooting RAW. Therefore, it lives in JPEG mode. The only time I shoot RAW with it is if I intend to do a lot of post production work (in my case, shooting IR and doing color channel switches and fake colour).
Even though I'm in the RAW brainwashee camp, I'd say Ken's advice is fine for most people in most situations.