If we had just one store to shop in on December 26th, we would choose Saks Fifth Avenue. Every year the store hosts an early hour doorbuster/ shopping event where additional discounts bring the total markdown to about 70% off.
The sale usually only lasts until noon and the crowds can be vicious. We suggest shopping on Friday and Saturday and finding a helpful sales person to pre-sale your items. This is one way to avoid the chaos and enjoy the extra savings.
P.S. Saks closes at 6pm on Christmas Eve but those last shopping hours are always thrilling and create wonderful holiday memories.