Do you spend extra time each morning warming up your car before you leave for the day?  I used to do that all the time.  Now I just jump in and go.  I give it about 30 seconds or so, but I've always read that with today's cars and trucks, there is no reason to sit and waste fuel and pollute the air.  Of course if you still drive a vehicle with carburetors and chokes, well then warm it up! Otherwise read these facts about it:

Eight Facts About Warming Up Your Car in Winter- Yahoo! Autos Article Page.