I don't ski, but I snowboard. Don't forget you'll be on your butt at times, so if you can beg or borrow ski pants it'll be a big help. Obviously you want the top layer to be waterproof/resistant, so no jeans, fleece gloves, etc..
Unless it's very cold you probably don't need quite as much as you think, maybe long underwear, a thin wool/cotton sweater and a waterproof/resistant shell and pants. Good waterproof gloves are important too.
I think after skiing/snowboarding is one of the few times Uggs look fine in public.
Have fun!!