I just had my first ride of the season in 35 to 40 degree weather here in Northern Florida. My face, fingers and toes are the most sensitive to the cold. Here's my temp ranges and what I wear.

65F and up: Jersey, shorts, regular socks and cycling shoes.
50F to 60ish: Jersey, arm-warmers, leg-warmers, full-fingered gloves, shorts, and cycling shoes, maybe a cotton shirt over my jersey.
Below 50: I'll swap the cotton shirt for my cycling jacket, add the balaclava, and throw a pair of actual shorts over my cycling shorts.

Plus, when I'm cold, I just ride harder. It works; Sometimes.

My gloves are leather-dress gloves so I'm looking at getting something better keeping my fingers warm. The Planet Bike Borealis looks like a good bet. As for my feet, aside from wearing another pair of my normal white cotton socks, I just try to keep moving my feet and toes. I need toe covers and maybe some socks specific to cold weather.

It's taken me a couple winters to really get it down to knowing how I should dress for certain temps. The key is layering and adding a bit more to the extremities than the core where most of the body heat is coming from. Through time, trial and error, you'll figure out what you need.