for commuting, I have a pair of leather Eddie Bauer gloves with a fake shearling lining. Those got me through last week's 20 degree, 12 mile commutes pretty well. For touring, I wouldn't carry them, unless I expected to need them for a significant amount of time, opting for layers that I could use in more than one way.

For touring when it was 38 degrees and raining in Utah and Colorado, I wore merino liners under nitrile/latex gloves, covered by a light shell. Those kept me going in that I didn't notice my hands as being the most uncomfortably cold part of me.

The merino liners alone were nice in a cool camp situation and for handling hot cookware - and the shells alone were nice when it wasn't that cold, but the wind had a bite to it. The nitrile gloves were handy for keeping my hands less grubby when I had to do some bike repairs in places without much wat4er around for washing.