+1 on the snow seal... it was always great in WI and has proven itself here, too.
For reflective stuff, X and I wear these in twilight/dark/rainy crappy days:
* Neon green shoulder and waist straps with reflective stripes provide 360° coverage for cyclist, joggers and walkers
* Central front and rear reflective safety zones further enhance visibility
* Fully adjustable straps with stretch material and Swift Clip™ allow you to customize fit
I just like it because it's easy on, easy off, and easy to throw in a pocket if I don't have saddle bags on. Following X at night, all I see is her red tail light, the silver 'Y' of the singlet, and a little yellow reflective triangle she has on her helmet, vs just the little red suzuki tail light.
Cagers are idiots- I don't give them much of a chance to screw up.
For 'unders' I wear my smartwool stuff. It's pricy, but I already had a bunch from when I was cycling all the time, and because it wicks almost as good as silk (but might be warmer) it's great for when I work up at the hospital. (people are real heavy to move...)
Smartwool midweight longjohns under my jeans, under my chaps (and REI waterproof/breathable rain pants over my chaps if it's really, really coming down- like I said, most of my real rain gear I have from cycling) My chaps have thinsulate panels that snap out, too, and they keep me pretty warm.
Smart wool light or ultralight shirt, then a columbia polar fleece jacket under my standard Joe Rocket Alter Ego jacket- it has a waterproof liner, but the outside still gets cold and wet. Fortunately the textile dries pretty fast...
wicking balaclava just squished under my chin, unless it's really, really cold.
Smart wool liner gloves in my usual buckskin gloves, and nitrile gloves over them if it's really coming down, because they're thin, cheap, and waterproof. might not reccommend it with most grips, but my renthals are really bitey and work ok with the nitrile gloves, even when wet.