My preferred gear in cooler weather is Belgian booties, heavier socks, knickers, ls jersey or ss jersey + arm warmers. Arm warmers are great since you can take them off if you get hot.
A wind vest is a GREAT investment. I have a Nalini one I got used for $20. The thing is as thin as a plastic bag but makes a huge, huge difference on cooler days. It is the difference between being happy and being miserable on a lot of days.
I also have two pairs of knickers - Assos Roubaix ones that I love (but the material around the chamois does seem to irritate my skin, unfortunately) and I picked up some heavier Capo ones that have wind protection. Got them on sale at the end of last year and haven't used them.
I own arm, leg and knee warmers. I don't like full tights. I have some PI ones that ride down the entire ride and drive me crazy. On in between days I just go with knickers over bibs + knee/leg warmers. Hot knees aren't the end of the world, right.
Knickers + wind vest are too pieces of kit I think everyone should own. And as others mentioned, wool is a great material for these, and superior to other fabrics.