Tablet PC's in Bright Sunlight?

chadma asks: "I'm developing a program to be used on a Tablet PC; the unit will be used outdoors >80% of the time. I've seen some tablets from ViewSonic and MotionComputing and wondered if anyone had any experience or suggestions in the best screen for high sunlight conditions. Has there been any study or anyone with experience that could suggest the colors we use in the design? Would a white background with black text be most appropriate?"