Shimano MW80's, used today for the first time but I'm pretty sure they'll top my list. So nice to go out on a cold day with a biting north wind and have warm feet.
They were among my 2007 best buys.
I wore them for about 8 months of 2008 because they are by far the most comfy shoes I ever owned and I don't mind hot feet.
On long Audaxes in winter I use an overshoe with them to keep the wind-chill factor down but they are fine in any temperature for a couple of hours.
They are a pain when water seeps in though as they take an age to dry. Best to wear waterproof overshoes with a high ankle if you plan to go out for more than 2 hours in heavy rain.
Having said that, you will have warm and wet feet rather than cold wet feet (using mesh shoes)