We're getting a blissfully slick snowfall here in the Northeast today, and it reminded me I need to get snow tires for NEXT winter. (We picked up our '05 the last week of January - figured we wouldn't need snows this year

.)
Anyway, if I had bought the X, I'd get new 18" wheels and summer tires, and put snows on the OE 17"s. Since it's a lease, I'm a bit hesitant to spend a grand or two on a full set up. Should I wait until September / October and get a Tire Rack wheel / tire combo for winter? Should I get second-hand rims and snow tires?
If you're leasing, what do you usually do? A newbie question for sure, but I thought I'd get a consensus here!