Katy, this year will indeed be interesting in terms of rentals. Here is my best shot.
The top end of the market will see a reduction in bookings as people scale back on high price discretionary items.
The middle end of the market may well see maintained or increased bookings as people trade down. They may also see less two week bookings and more one week bookings.
In all cases i would expect to see more last minute bookings and more haggling from those making last minute bookings. In my first year of renting most of my bookings came in January and february. Now its more like april and May.