I've had really good luck with the MEC firestarter gloves this year (subzero night rides). Multi purpose glove, so not quite as tight fit as specific mtb product, but found a size that's more than adequate for me. Cheap, thicker finger/palm material for more insulation, a tiny bit of insulation in the sandwich, and a water resistant outer material. I think the best part about them (other than price - I'm cheap) is the long elastic cuff that keeps all the heat in.
I also use them for Skate-Skiing and every day use as well, so they're well worth the $30 investment.