There's also the DIGIC III Image processor, and ISO as high as 1600, but everybody comes for the basics: 3x zoom, 7.1 megapixel CCD and a 2.5-inch LCD in each shooter. The $300 SD750 gets a bit fancy on form factor, but manages to be a mere 0.75-inches thick, while the 4.5 ounce SD1000 keeps the the classic ELPH look and also retails for $300.
