Despite the breathless claims emblazoned on their bodies, the SR7 and CX7 use 3.2-megapixel sensors, while the and SR5 uses a 2-megapixel sensor. All have 10X zoom lenses.
The SR7 outbulks the SR5--the lens extends a bit farther to make room for the manual focus control--but both support NightShot mode and Dolby 5.1 audio recording.
Sony probably shouldn't have included this photo of the touch screen in the hands of an actual person; you can see just how the small the 2.7-inch LCD and virtual buttons are, which is one of our primary complaints about the interface.