So here is a breakdown of what I ride in the winter. This has been a process of trial and error and is different for everyone. Most of my gear I begged for for Christmas, I wish I had the funds to go randomly try the latest multi hundred dollar gear.
On the bottom I typically wear my Velorochester bib shorts. If I know I will be out there for awhile under 0 degrees I may throw on my craft base layer. If not, the storm tights I use are by far the most impressive piece of clothing I own. They really are great at a huge temp range, maybe +30 to -20ish. It is hard to be super accurate because despite my pleas, the weatherman does not bless us with a lot of sub zero weather. My coldest ride this year was -4 up in Cable. The base layer got the nod and I was snuggley warm.
Up top I will typically wear a craft base layer, then my 100 ounce bladder (not pictured), a cheap Bellweather rain jacket, and an older Nike winter cycling jacket. I sweat a decent amount. If that sweat gets into the jacket it can freeze and cause me to lose insulation properties. I have actually had my arms start freezing up before. This set up is hot for 20 degrees+. Arrowhead last year I was hot quite a bit, but my jacket stayed dry and when the temps dropped I was not in trouble. For regular rides I will forgo the rain jacket at warmer temps, but it does allow me to ride about 15 degrees colder. If you want, you can google "vapor barrier" and find out more info, I will not try to explain it all. Plus, it is not for everyone. I definitely prefer it. I rode at Arrowhead in -20 temps with this set up. I have a super warm Nike thermal hoodie to go over if needed.
On the bars I upgraded to the Dogwood Pogies. First year I used Bar Mitts, and they are adequate, but lack in many areas. I would use those for commuting maybe, but nothing else. Then for 2 years I used a pair of ATV pogies I modified some with good success. The Dogwoods are not necessarily warmer, but they do the job much better than my old set up (they do make a plus version that is much warmer). Thanks Fatbikes.com for the pogie hook up! Underneath it my favorite mountain bike glove ever, the Bontrager Rhythm
Onto my feet. I start with a thin base layer, than a baggie (usually Target as that is what we have a lot of) and then a thick Wigwam -40 sock. My feet run a tad on the cold side. I got myself a 45Nrth boot a few sizes too big, I added my insole from my big lakes to the inside (that is 2 insoles if you are counting), and I still have a bit of room. I may add a thin or med weight sock when needed, but this set up was toasty on my -4 degree ride. These boots are definitely warmer/nicer/better than my big Lake boots with booties.
Up top I always have my Cold Avenger on. It keeps my lungs SOOOOOO much happier. Unless I am in a full on XC pace, I notice little to no resistance. I took it down for most of the race on Saturday and payed the price for it later. This mask keeps me head really warm and ears covered. The temp needs to get about 0 for me to throw a hat on, and it is usually a dry fit like this Arrowhead finisher hat.
So there you go on my little "what I do" tutorial. To give you an idea, the things I actually paid for and did not get as gifts of some sort are the shorts, base layers, rain jacket, and socks. Like I said, I wouldn't mind having access to trying different things, but this sport is expensive enough. The funds are not there to do everything I would like, but I have come this far after many years.