Eric, like you, I have trouble with the psychological aspect of going out with less clothing mass. After all, the number one reason hikers perish is from exposure. You always read things like: "..he evidently was not planning to stay the night because when the snow melted in spring and his body was found, it was clad only in a light nylon windbreaker.."
But seriously, I suggest going out for evening walks now in the winter to test the warmth of various clothing combinations and to gain confidence in them. This has been a great way to learn about fabrics, moisture transport, etc for me. I started walking here in my down jacket; now I go in a wool-1 long-arm zip top, nylon windshirt, watch cap, and gloves (and pants of course). I learned insulating your torso is little use if you are loosing heat from head and hands.
So for the most bang for the buck? Id start with dual-use items..
1. A merino base layer, top and bottoms. These changed my comfort level dramatically and I wear the bottoms every day.
2. Synthetic high-loft jacket such as Montbell Thermawrap, Patagonia Micro Puff, or a sports-store inexpensive version. This also is useful around town.
Your list is actually a great example of how to start out with economical gear.. and its better than the cotton stuff I started hiking in!
I suggest reviewing the clothing lists of those who have posted them at their profiles. My overnight list good to 20'F is:
Wool-1 top, bottoms, socks, glove liners, and watch cap
REI Summit convertible pants
Fleece 100 zip top or
Fleece 200 zip top or
Montbell Thermawrap jacket
Montbell light alpine down jacket (below 20'F)
Montbell Thermawrap pants (below 20'F)
Wind/light rain layer:
TheNorthFace DIAD jacket(replaced multiple heavy jackets!)
Montbell UL wind pants
Vapor barrier layer:
Marmot Ion full zip
Heavy rain layer:
Columbia full-zip goretex pants
I got almost everything here at steep discount and you can too; watch steepandcheap.com, and use froogle.com to scour the internet daily for closeouts.
Let us know what you decide on?