The Apple Store app has received a nice upgrade, adding several new features and international support for Canada and China.
One extremely nice feature is a personal pickup option, something I've used at Best Buy at times. Buy a product through the app and arrange for pickup at the Apple Store of your choice within an hour, depending upon stock availability. For those in a hurry, this will greatly cut down on the time and the hassle of fighting through the throngs of customers in a crowded Apple Store