I warm up very quick and sweat a lot, that's why I am usually looking for the most breathable equipment. My chose is regular fleece plus a breathable wind breaker on top if there is wind. (Please refer to this article: Fleece or Soft Shell?). But for the rain I also carry a waterproof hard shell.
When would one carry both a wind jacket and waterproof hard shell?
When would one carry just one of each?
When wind is guaranteed but rain is unlikely you might decide the extra weight is worth it. But good layering with a hard shell that is breathable and has underarm zips can be quite comfortable while saving you the weight of the soft shell. This is my preferred option as the times I get too hot are generally when it's raining. Wind blocking fleece is an alternative too.
When cool temperatures and wind is a concern, I use a thin, very light windshirt. If it is cold enough to need fleece, the windshirt comes off and the fleece goes on. I have a new, fairly densely woven fleece from Patagonia that offers some wind protection but not is not rain resistant. If more protection is needed, a light rain jacket or heavy rain parka goes on top of the fleece. Because at that point, the weather is usually cool enough that I can adjust the zippers on the fleece and jacket to prevent overheating. The windshirt adds almost no weight to my pack. When cycling on cool days, I often through the fleece over the windshirt at long stops.
Your needs will depend on the local climate, I live where it rains often but is usually not misty. In areas with persistent mist and dense fog, a different layering system might be better.
