Some will argue that the iPhone 4 should be on this list, but Apple's iPhone had a very humble beginning when Steve Jobs introduced it in 2007. An intuitive interface, a touchscreen that supported multitouch gestures and the best mobile Web-browsing experience were just a handful of the reasons Apple was able to sell a million iPhones in just 74 days. That figure pales in comparison to the 1.7 million iPhone 4s sold in just three days, but the iPhone existed an entire year without the App Store — which became a major reason for the iPhone's success. Regardless, the original iPhone rocked the mobile-phone industry, and its competitors are still struggling to catch up.