Suggestion from one also has sweaty palms. Get anything that has a breathable waterproof shell with a removable insert that is made of a sweat repelling material (like fleece). For a colder day, an one piece made of breathable material will work. The key is that you don't want to trap in sweat in the material that is touching your hands. Once your sweat turns cold, your fingers will freeze. A glove with a hand warmer pocket is nice too.
If you want to take a chance on fit, sierratradingpost.com has quite a few selections available.
My hands also would sweat like crazy with leather gloves, they got wet and stunk, and would be cold. I tried cheap, fabric gloves, (no leather) and have been very happy with them. They don't hold up for more than a season or two, but they are cheap, and you can wash fabric gloves. Leather palms are OK , but not nescessary. Once or twice I had gloves with gore-tex liners, didn't seem to make any difference. I think the key is to have breathability in the gloves so the moist sweaty air can vent out.
I can usually buy gloves like these for $10-15 at the end of the season at clearance stores like TJ Maxx and Marshall's.
No more expensive gloves for me.
I have a pair of the Burton Gore-Tex gloves that I love. Good insert, good glove, great quality. Has some ventilation pockets that might be useful for you (that double up as hand-warmer pockets). When I get sweaty I just take off the shell for the lift ride up and pull them back on when I'm at the top. Just don't forget to wrap the safety strap around your wrist .
I've been wearing Goretex gloves by Ruesch the past couple winters. They breath well and don't get wet even when it rains. I've paid $20 a pair for them at a local sporting goods store, and get a hundred days out of them before they start to wear through. Unfortunately, I lost one on the last day of the season last year. I needed gloves again, so I found some Dakines on tramdock.com for $28 which are also Goretex (I've become a believer in Goretex everything). They seem to be very well made, but we'll see who they hold up.
I ski in nothing but Spring gloves for the same reason. My hands are always warm so light gloves and no sweat means comfortable. Go to level9 sports right now and Scott Springlight gloves are only 15$. A real steal.
I have to agree that more good choices are offered by the snowboarding industry. It's pretty hard to find good ski mittens made by ski glove companies.
I like the fact that the Burton mits (and some of their gloves) come up a good ways and over the cuff of your jacket. Plus, they just feel like their well built. I'll alwys a pay a little extra for a good pair of mits or gloves. Saving $ doesn't seem like a good idea when you're hands are numb.
Pick a glove with a warm, removable fleece glove liner then buy a cheap fleece glove of about the same weight as your second glove liner. I'm not talking about the thin aftermarket products designed to fit into a conventional glove. Exchange as needed. Wear both in the AM and let both dry at mid-day.
My family has found one of the big advantages of the fluffy removable liner is that it is MUCH easier to dry out the gloves a little at lunch, and completely overnight, because you remove the fluffy liner and get more air circulation and twice as much surface area exposed to the dry air.