Apple iPhone (AP Photo/Paul Sakuma)

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Units sold: 129 million

What more can we say about the iPhone? Surely, you've tired of headlines detailing the popular touch-screen and its much-hyped fifth incarnation, but let's give its previous four versions a little credit. Remarkably, the iPhone hasn't always sold like mad - despite debuting in Q3 2007, the iPhone never sold more than 2.5 million units until Q4 2008, when it moved nearly seven million of the gadgets worldwide. Since, however, the iPhone has in no uncertain terms become the most coveted smartphone on earth, selling more than 100 million units in Apple's last eight reported quarters alone. The frenzy surrounding the iPhone 5, which has already been forecast to sell 25 million units by the end of 2011, will surely pad those numbers.

* Video: BlackBerry or iPhone?