I have used various knee warmers under Mocean bike patrol pants, with long Smartwool socks as needed, but late last winter used Assos Roubaix bib knee-length tights for the first time, on a cold evening ride, and it was heavenly. I think I wore the Mocean pants over the Assos tights, but the Mocean pants are merely to keep wind out; they do not increase actual warmth. I should add the disclaimer that winter is not very cold here; the average January low temp is 40-ish.

I wear standard roadie lycra. I agree that they look silly, so I wear my mountain bike shorts over them while commuting. Good to about 20F or so.

I wear shorts down to about 55 or so...knickers down to 45 or so, J&G patrol pants below that...with poly long johns as needed.

Poly long johns and windproof lined cycling pants works fine for me down to 0f or so. Colder and I put a pair of pants on top of them. Don't recall the brand on the pants offhand but the REI ones are probably similar.

I use this part of DJ's list. My girlfriend doesn't think I'm spandex worthy - especially when I stand on her front step wearing the tights. She prefers the jogging pants on me then.

I wear Mt. bike shorts that have the dual short, Lycra and a short over the top. Then when the weather gets colder, I use a Peral Izumi pants that are wind stoppers. They aren't tights but they keep the cold out. If it getts too cold, I will put a pair of thermal pants on then add a older pair of ski pants.

Just the other night I was out for late night ride, and our low was a few degrees F above freezing. I was just out for a cruise, and I was wearing a hoodie and warmups -- I was quite comfortable. Probably wouldn't wear this for regular riding, but for the "I can't sleep" ride it was perfect

The winters here are full of wind and clouds, and about half the time 35 degree rain. The classrooms at school can also be cold as b@lls in the winter. So for me its hoodie beneath my leather jacket motorcycle jacket (for that cool urban look LOL) and flannel pajama pants beneath jeans. When raining, I substitute the leather for a fleece lined, waterproof rain jacket. It's what I have, so its what I use.
On sub freezing days, some kind of face covering may be required.

Shorts/knickers down to about 50F (you should really keep your knees covered below 60F even if it doesn't "feel" cold enough to do so). Then I add thermal tights (Pearl Izumi) down to about 30F. Below that I'll swap out the regular knickers for some heavier wool pants or knickers (still retaining the tights) and wear some heavy wool socks. If it gets really cold (near 0F) or windy, I'll add a pair of long johns. If it is cold and rainy, I wear a pair of old waterproof, windbreaker warm up pants over everything.

I can highly recommend pants.

Regular guy duds. Nothing fancy.