Update: Currently (2/1/2010) the Moment is the #1 best selling smartphone!
The Samsung Moment is a very popular phone - at least over at Amazon.com, where it's currently the #4 best selling smartphone. It's more popular than the Palm Pre (also on Spring, and costs the same, $79.99). The most popular smartphones, by the way, are two BlackBerrys (Bold 9700 and Curve 8900), and Motorola's Droid. The Moment has a 3.2" touch OLED, full QWERTY slider, 3.2mp camera, microSDHC slot, Wi-Fi and GPS. It runs Google's Android OS (on a 800Mhz processor).
Another OLED gadget that is popular is Nikon's S70. Despite getting rather bad reviews, it's number #13 and #14 in Amazon's best-selling point-and-shoot cameras. Different colored S70 are listed as different products, so totally it should rank even higher. The S70 has a 3.5" touch OLED. The S70 costs 260$.