RAW vs JPEG noise comparison
A quick comparison of noise levels in RAW vs JPEG at ISO1600 on the 450D. RAW file given a bit of NR and sharpening in Bridge is a bit less noisy than the in-camera JPEG, but you could apply the same NR to the JPEG anyway.
I will still continue to shoot RAW for the other benefits, but I can't see any advantage of shooting RAW as far as noise levels go for well exposed photos at high ISO.
Edit: Seems Flickr doesn't save the original file size, so you can see that here: static1.davidkennardphotography.com/wp-uploads/RAW-vs-JPE...