A few years ago, totally without any planning on a 4th of July sale at their outlet, I bought a two piece deal from Eddie Bauer with a fleece lining and a waterproof shell. All I wanted was a waterproof jacket, but this was significantly less money at 80% off than just buying a waterproof jacket

You can wear just the fleece when you just want the fleece
You can wear just the shell if you want a waterproof jacket and it's not that cold out, with or without the hood depending if it's raining or not
You zip the two together when it's really cold, or you want to be warm and dry in snow and rain.

It's become my favorite jacket and unless it's really really cold out.

Unless you are always someplace where you know day to day what you will need, I think you are better with a modular solution, it takes up no more space than a single use winter coat would.