Thanks for all the responses and advice!
no1mad, Scheherezade, puppypilgrim, DX-MAN - I tried starting off cold today as yous suggested and it went okay. There was some ice on the road which made it difficult to really get going (mostly cause I was afraid of crashing).
Jose Mandez, colleen c, exile - Layers sounds smart and safe, but kind of like a hassle. Still, I think I may invest in some thin ones as suggested and try it out.
Jim from Boston - that thread was handy also, I didn't mean to be redundant.
Beside trying to find a good balance, my other concern is emergency situations. Like if you get a flat, and have to stop to fix it, or wait for a bus. Do those who dress light just suck it up and tough it out, or do you have contingency plans?