I did my most serious winterizing back in May. I did to my 1st floor what I did to my 2nd floor 2 years ago. Took down all the vinyl siding, removed the old windows (1994) that the builder never bothered to install properly (no caulk, no flashing, etc.). Wrapped the house with Tyvek, properly installed new energy efficient windows, put back up the original vinyl siding. It made a huge difference in comfort in both summer and especially winter. When the wind would blow the bedrooms on the upwind side of the house use to get 10 or more degrees cooler than the downwind side of the house, now it is consistent everywhere on the 2nd floor. I think we'll notice an even bigger improvement on the main floor where we spend most of our time. I think it will have a bigger impact on the energy bill as well. It sure made a difference this summer as well, record heat, record elec. bills for the average MI resident, and my bills were down a bit. I ran the A/C all summer as well, due to allergies we pretty much have to. I did drain out the garden hoses and put most of them away already. I still need to winterize the RV but we'll be using it again in a couple of weeks so I'll just keep an eye on the temperatures.
As for car winterizing, I'm thinking of getting the winter wheels/tires down for the wagon already as this year it has performance summer tires on it for the 1st time. I've always used all season tires in the past for the warmer months so the transition to the Blizzaks was always flexible before, not this time. I don't want the wife driving around a RWD V8 powered vehicle with no traction control and a limited slip rear with summer tires and frosty (or worse) roads.