Proper clothing is important when skiing, and while I rarely concern myself with being fashionable I do not want to look like a dweeb (gaper, gorby, jerry, etc) anymore than I want to look like a dandy either. My main consideration when dressing for the ski hill is comfort and looking good is secondary.
Most people who live in cold weather climates understand the concept of layering but not always. It drives me nuts seeing people walking around wearing shorts and jacket in the winter time, at least, I do not hear them whine about the cold, but those are not the people whom I often am around so I do not get to here them talk about anything.
I layer it up on the top. Only if it is real cold (and that is probably 5° F or below & no sun, or maybe a little warmer with high winds) out do I wear long-johns, though I always wear three layers of socks, a polypropolene pair, a pair of cotton athletic socks, and then a pair of technical socks. I have a pair of raggedy old Levi 501s with the cuffs walked off and cut up, so it is easy to get them over my boots (these trousers I avoid wearing when working a chainsaw).
Up on top, I usually wear a cotton t-shirt (again if cold then I wear a polyprop. shirt), topped by a long-sleeve shirt, and then one of my 100% wool sweater. I may or may not pile a hooded sweat on top of that. Once I am set there, I wear a pear of Obermeyer bibs down below and a Columbia gizmo on top.
Once I am skiing, I can then gauge how things really are and a quick trip into the lodge I can pull off a layer or two to suit the conditions. Late season skiing I usually forgo a layer or two and wear a fleece over the top or another more “workman-like” jacket I have.