Wednesday I finally got to test out my new biking apparel with some actual winter weather (not the 69 degree temperatures last week that had me back to shorts and t-shirt). It was 7 degrees with a stiff headwind when I rode to BC and I wanted to find the right balance of clothing so that I would be warm without getting sweaty. Last time I biked in this weather, my core would get too warm with a nylon shell over fleece or wool while my extremities, especially my feet would get painfully cold.
The major improvement I've made this time around is buying an REI Neo soft-shell jacket made of stretch-woven nylon that blocks the wind but also breathes enough to avoid trapping moisture from the inside. For most weather between 30 and 50 degrees, I can wear this over a single REI polypropylene base layer and tweak my temperature with different head coverings (thin balaclava and fleece neck gator). On my lower half, I wear a pair of stretch-woven nylon pants over biking shorts, with Smartwool snow-boarding socks and Shimano biking shoes on my feet.
When the temperature dropped into the nippier range on Wednesday, I just added an thermal underwear top and bottom underneath my normal outfit. With both head coverings thin balaclava and fleece neck gator and my warm mittens, I was able to stay comfortable most of the ride after I got warmed up enough that my body heat began escaping through the only uncovered area of my body-my eyes (I'm not ready to wear ski goggles yet-that would take things to a new level of biking dorkiness). I was impressed at how warm my feet stayed thanks to the Smartwool and the Shimanos (with are thicker than my old Nikes). On the whole, this combination felt just right--not to cold, not too sweaty.
So that's the gear report for any of you who bike in the winter. I'd be interested to hear if anyone has other all-weather biking gear that they recommend.

Gear
Tim--I've been looking at those Neo soft-jackets. They seem really good at blocking the wind. We don't have anything like your temps but it HAS been cold, here, in Northern California, and when it's cold there's usually a cold headwind for us in the morning.
When I biked in Boston in the winter I used a neoprene skiing face mask, a thin neck gator over my head and ears, and a fleece neck gator over that. Normal footwear, but I wasn't going your distance, either, which meant I had fewer issues about arriving too hot and sweaty. This is now over ten years ago and the gear has improved significantly since then.
BSAG over at But She's a Girl has a new take on how to do the bike commute without roiling yourself up: ride at a more stately pace (she's ordered one of those beautiful old Dutch bikes). See http://www.rousette.org.uk/blog/archives/cycle-commuting/
Good ideas
Thanks for the recommendations, Pica. This weekend I'm going to look into some other ski masks/neck gator combos to see if I can find anything that works better for extremely cold weather like today (2 degrees and windy).
I think BSAG's suggestions about riding at a more stately pace makes sense if you're hoping to biking to work in your work cloths without too disheveled. Now that I'm taking my clothes to work and showing there, I usually try to keep the pace up to get a better workout. And on a day like today, I need as much body heat as I can muster to keep comfortable, so the stately pace will have to wait until summer.
I am pleased to hear about