iPhone 4
This changes everything. Again.
Background
Introduced in June 2010, the iPhone 4 replaced the iPhone 3GS, and included the same Apple-designed A4 processor found in the iPad. External improvements included a slimmer, redesigned case, a 5 megapixel camera with LED flash, a VGA-quality front-facing camera, and a stunning new 960x640 LED-backlit display. Apple claimed that the new display, branded the "Retina display," was so high-resolution that at at standard reading distances, the human eye would be unable to distinguish individual pixels. Under-the-hood improvements included the aforementioned A4 processor, a faster graphics subsystem, improved battery life, and a 3-axis gyroscope which, when combined with the existing accelerometer, provided 6-axis motion detection. The iPhone 4 included the newly re-branded iOS 4.0, which brought a number of improvements, including multitasking and folders. In addition, the iPhone 4 included a new video calling feature, called "FaceTime," and the capability for 720p 30 fps HD video recording and editing.