News media, investors, and Twitter users everywhere expressed feelings of being “underwhelmed” by the Apple 4S announcement last week, but that didn’t stop the latest iteration from having its best pre-order day ever, breaking the one-million pre-order mark in 24 hours for the first time in company history. The phone is identical to the iPhone 4 in appearance, but it’s now powered by a dual-core A5 chip, has an upgraded 8MP camera with improved optics, offers iOS 5 and iCloud, and introduces the personal-assistant software Siri. “We are blown away with the incredible customer response to…