Howdy. I guess it shouldn't be a surprise that my first post here should be about commuting. : )
I'm in the the DC area too (College Park). This morning I was out early poking at puddles to see whether ice was forming. I'm running 50mm Big Apples on my Hybrid right now, but I think that just gives the bike more surface to get out from under me--I ordered some Nokian Hakkapelliittas the other day for these sunny days and freezing nights. My commute is 5 miles betwen 5:30 and 6:00 AM, so the ice is sometimes hard to see.
I like the UA stuff OK, but I'm absolutley sold on a light silk base layer topped with SmartWool and a Goretex pullover. I add a light wool sweater or microfleece vest in the lower 20s and below.
Still and all, my morning commute is the highlight of my day. More than once I've rolled into work feeling sorry for all the people who "have" to drive...