At No. 2 is Apple's newly released iPhone 4. Measuring 4.5 x 2.3 x 0.37 inches, iPhone 4 has gone sleeker, more angular and razor thin than its predecessor which is nearly half-a-inch thick. Apple's fourth-gen model comes with 3.5 inch display with 640 X 960 pixel resolution. The phone packs Apple's latest mobile operating system iOS 4. Among other things, the new OS promises features like multitasking, spell check, Folders and iBooks.