Dakine makes a whole bunch of great 2 in 1 gloves and mittens.
I've used these for a season and have no complaints so I'd like to 2nd this statement. Granted it was relatively warm when I was out last season so I can't really speak to their warmth in the cold, but my hands were definitely hot with the liner in. If you want to shell out more money the next step up looks like the Titan Glove which Goretex material.
Dakine Gloves : Scout Glove