I've been thoroughly disappointed by most gloves. Pearl Izumi lobsters are often billed as the warmest, but they really SUCK. They're good to around 30 degrees only.

I bought some generic lobster mits on eBay last winter that were made out of thinsulate and were the best I have tried, but still not great. I haven't found ANY glove after spending about $300 on various pairs that I can comfortably ride in under about 15 degrees.

EDIT - here are the eBay gloves, they're "Craft," and they're cheaper and superior to the Pearl Izumi's without a doubt.
http://cgi.ebay.com/Craft-Split-Fing...d=p3286.c0.m14