I use layers. Part of the challenge for me is not sweating. It's easiest if I don't have to change clothes when I get to work, but I haven't found a great solution, so in the extreme temps (extremely cold & extremely hot), I end up wearing different clothes for my short commute and changing when I get to work.
When the temps are in the 20's (F), I wear a merino wool undershirt, a light windbreaker, and my goretex rain coat (Phantom). The wind breaker & rain coat are cycling specific so they are the right shape. They don't get tangled, and they don't leave a cold bare gap on my back when I'm leaning over the handlebar. However, a non-cycling specific light jacket & outer shell to block the wind would probably do fine.
It seems like not much clothes but it is enough for me at that temp. The balaclava, gloves, wool socks, and long johns or leggings under my jeans or slacks complete the rest of it. And a thick layer of vaseline on the part of my face that isn't covered by the balaclava.
I'm not sure what you mean about the jacket being work-professional. I take my jackets off when I get to work. The one thing that does cause me problems is if I need to go over to the other building on a cold day. What works for biking in the cold isn't nearly warm enough to walk 3 blocks. Sometimes I just sprint. However I have enough coats that I should probably just leave one in the office.
2009 Trek 7.2FX WSD, brooks Champion Flyer S, commuter bike