Happy with the Planet Bike Borealis, they have a liner that you can swap in and out with your own gloves to tune the temp.
Borealis

For really cold, and with a flat bar. I use a set of pogies:
IMG_2391 by mbeganyi, on Flickr

by mbeganyi, on Flickr

These are cheap ATV ones from the hunting section... but they work. I usually just wear a thin liner glove.