Most of these things we call pumpkins. And we eat them, often! Any time I have a meat and three veg type of meal, you can bet that one of the vegs will be pumpkin. Butternut is definitely a variety of pumpkin, not squash, by Australian terminology. Over here squashes are (almost ?) exclusively teeny little things, not more than about 15 cm in any dimension. I'm told that zucchini and pumpkin are actually the same species though, and if you plant seeds collected from a pumpkin plant that was next to a zucchini plant, then you get some very strange fruit from that plant!

Richard.