We booked for 2011 also and it does not include the $500 bonus. The perk for booking so early was the reduced 2010 rates. However, if they do offer the bonus in the future, and you bought the insurance, you can cancel and rebook at the better deal.
I believe the "Best Deal Guarantee" is included, no insurance is necessary to get the lower rate.
You're right about the best deal - thanks for clarifying! If a lower hotel rate is offered you get it without penalty, insurance or not. However, if a special is offered, such as the $500 bonus which is typically only offered on new bookings, then you would have to cancel and rebook to get it. The best deal doesn't cover that but insurance would. But Couples rocks for making sure we get the best price on the hotel!