What a timely topic, as every time Ive tried to ride outside lately there is no temperature to be found. Who stole my temperature?
Unlike a lot of body parts which can just be swaddled in ever more stuff, there comes a point (and pretty soon) where trying to warm your hands can compromise all of the rest of your body parts. My ninja like bike handling pretty much goes out the door when I'm wearing snowboarding mittens. Lately it's been cold enough that I don't care. Corners can be taken slowly, shifts can be missed, but the maintenance of digital happiness is paramount.
Above 50 or so, almost anything works. I like long fingered mountain bike gloves well enough, and the pair I have from Fox is about 8 years old and running strong. If racing in moderate cold, construction gloves work fantastically well. The grip is relentless and they are seriously cheap - like a buck a pair. Don't tell anyone but I usually heist a couple pairs a year from our supply locker. Since my guys usually go through about a case a week, no one notices
From the point of "my it's a bit chilly today" down to "frozen snotcicles certainly ARE this year's must have item," neoprene sailing gloves rule. Dexterity is top notch and warmth is good. They have a close fit, so liners aren't really an option. The pair I use are "frostbite gloves" from Musto. Www.musto.com for info.
The next step is spring skiing gloves, made famous and still made best by Marker. Any worthwhile ski shop in the universe has them in your choice of white or black. You can go with a liner on these, which sets you up well to somewhere not that far below freezing.
In my quest (entirely unintentional, btw) for waffle points this year, I've just gone with full on ski mittens several times. Dexterity < 0, but it is brilliant to be ride in that much cold yet enjoy toasty warm hands. Whatever kind you like will be more than adequate. Surprisingly, the cycling dexterity of mittens, by the time you've gotten to full on gore tex ski mittens, is about a wash between gloves and mittens, and the mittens are easier to take on and off plus just ridiculous amounts warmer.
Hopefully this turns into a temporary moot point again real soon.