This page began as a usenet article that I posted to rec.food.veg.
When I cook with my wok, I use a bit of oil and cook the food very fast, flipping it around all the time. This is the point of the shape of a wok - the food is intended to be kept constantly in motion over a large surface area. The fact that the food is coated in hot oil means that it continues to cook even when it's being flipped around.
I prefer to use my non-stick frying pan for water-sauteeing because it allows all of the vegetables to remain mostly in the saute liquid. If you used a wok for water-sauteeing, you'd either need to use a lot of liquid (hence in my opinion missing the point of sauteeing rather than boiling), or have most of the vegetables poking out of the surface.