I agree on that "winter collection". I had a very limited set of kit and used to batter on in bib shorts and SS jerseys because I tend to "run warm", much to the amusement of my friends and fellow club mates, but having experienced some discomfort in my knees and mentioned it to a few people was advised to wrap up a bit so I gave in and bought the equivalent of your list. I have 2x pairs of arm and leg warmers, one pair plain lycra, one pair roubaix. A pair of warm bib tight's (The Castelli Sorpasso linked above). I didn't bother with non-warm (fleecy) longs, since a pair of comfy bib shorts with lycra leg warmers is essentially the same thing and more flexible.
Top half, a few base layers and a nice wind stopper(front) roubaix (back) jersey and a packable rain jacket.
Other than good gloves, overshoes and maybe some headwear that is very much all anyone will need for winter.
I do also have a superflous winter skinsuit! It was a completelly self indulgent purchase but quite frankly having tried one on, I couldn't not have one! It is the most comfortable piece of kit I own. The top half is fleecy inside and has 3/4 sleeves which are great for those in between days or for creating a superior seal with arm warmers when it is very cold, the shorts are simply very high quality bib shorts, very slippery and smooth. Being a 1 piece, with a full frontal zipper, there are no need for any bib straps to potentially rub your erect nippies and you can take a piss very easy. As I said, it was a non-essential purchase, I had the money and it was a nice bit of kit so I bought it without much thought, i have the tendency to do that occasionally. Practically speaking I would mostly use this for early season TT's and bad weather TT's, but it is also nice to wear on occasion just when you just want to feel good when the weather says you ought to feel otherwise!