Beautiful photos - not the easiest places to lug a digital SLR, but well worth it!!
Re the yellow halo around the Midi arete photo, my wife has found this with her Nikon D70, it doesn't like highly saturated yellows (in her case it was a shot including buttercups) and tended to clip some patches of yellow into red. Nikon themselves couldn't find any problems, and replaced the camera with a new one which still did the same...