Sharpness: The central areas of the SD770 IS' photos are sharp, and in fact look slightly oversharpened. It's especially noticeable since sharpness decreases dramatically around the sides.
Noise: The SD770 IS' noise profile looks pretty typical for its class. Up to and including ISO 200 you're pretty safe; above that, you can start to see blurring, artifacts interfering with detail, and texturing in solid areas.
Distortion: Wide-angle distortion actually looks pretty good except for that upper left corner squishing which is typical of compact cameras.
Color: By the numbers, the SD770 IS displays excellent color accuracy. Visually, the hues look correct, but in some cases hypersaturated.
Fringing: The SD770 IS shows surprisingly little fringing. As with any camera you'll see a little purple on a hotspot, but more typically the worst we see are some subtle cyan or magenta edges.