Gloves & Mittens
Gloves or mittens are necessary to keep your hands warm. They should be waterproof, windprooof and insulated.
Gloves are the most inconsistent item of clothing and cause the most problems, especially for first timers due to the fact that gloves are not available for hire as a hygiene standard. Because of this first timers will usually buy the $15 pair of gloves at the rental store and will regret it tomorrow.
All gloves get wet. This is the inevitable. However when $15 gloves get wet they also get very cold and then your hands get very cold too. When your hands get very cold they get very painful.
There area few ways to avoid this but which way completely depends on the situation, what you are planning to do, and how long your staying for.
If you are at the snow for just one day and are not skiing or boarding then $15 gloves are usually fine (anything else is usually a waste of money as you probably wont be using them again).
If you are at the snow for just one day and you are skiing or boarding then just get some good gloves. Even when you aren't touching snow, gloves still become wet skiing and boarding.
If you are at the snow for more than a single day, doing any kind of activity, good quality gloves or a pair of spare gloves are a must.
Hint: If you want a "golden bullet" solution, just buy a pair of HIGH QUALITY gloves, it will cost more but it will work in any situation.
The most important thing that will keep your hands warm is adequate circulation. Your body is a furnace and the heat is distributed via the bloodstream. Your body will cut off circulation to your extremities (including your fingers) if it detects that core temperature is falling. If blood is not flowing to your hands, either because your body has reduced bloodflow or because of external constriction your hands will get cold. Ultimately warm hands depend on a warm body. A consequence of this is that, if you load your gloves up with inners and handwarmers, you may restrict circulation to your hands. If the blood is not flowing, your hands will freeze. Everything else in his topic depends on adequate circulation. If necessary, if you use liners etc, you will have to buy a size larger glove or mitten.
Your hands sweat. See waterproof/breathable under How to Choose a Parka.
A great option is gloves with a waterproof/breathable shell, and removable fleece liners. Washing (and desmelling) are much easier, and on spring days you can either ski in the liner or the shell and be comfortable.
Leather is an option, but leather requires maintenance to keep it supple and waterproof. A well made leather glove is a pleasure to wear. The drawback with Leather gloves is that they aren't really waterproof, so if you are skiing in Australia they often aren't suited to the conditions (ie sleet/rain).
Look for reinforcing on the palms and where you grip your pole or wherever boarders experience wear, like on the knuckles. Some gloves also have integrated wrist guards, which are a good idea for boarders.
Gauntlet style gloves that extend up your forearm are a good idea because the more overlap you have the less weather penetrates. These are often sold as boarder gloves, but it is an area where boarders are undoubtedly ahead of skiers. If time is important it is harder to read your watch.
Gloves help dexterity. Mittens are warmer. There are hybrid gloves around that have a separate index finger, and the other three fingers are in a single pocket. These have most of the warmth of mittens, but allow some dexterity with the index finger. They are called lobster claws for reasons that are obvious when you see them. What you need depends on your metabolism.
Most of the big manufacturers like Swany and Kombi have two-piece gloves with a thin fleece liner and a nylon breathable waterproof whatever fabric outer. This is a versatile system, as you can peel down to the liner only on warm days, use the outer only for wet mild days, both together as things get colder. The downside is now you have 4 pieces to lose instead of the traditional 2.
It is possible to get lightweight inner gloves, made of silk or synthetics that can be worn inside your normal gloves. The extra layer provides additional insulation. You can also get chemical warmers to place inside your gloves. These last all day and provide warmth.
If skiing/boarding a lot consider a few different types of gloves with different ones suited to different conditions. eg a warmer weather spring weight glove, a general purpose glove, a damn cold day glove and a wet weather glove. If you just have to be out in the wet weather then consider a woolen inner inside a thick vulcanised rubber glove - may not be fashionable but keeps you warm and dry!