Digital Photgraphy Review has a review of the Canon G6, in which I have sentimental interest (I used to own the G1 before my current S1 camera).
Primary features of the US$700 camera are (comparison with S1 in brackets):
• 7 megapixel: resolution 3072 x 2304 -- (3.2mp)
• Movie clips, best quality: 640x480, 15fps, 30 sec -- (640x480, 30fps, 8 min)
• Zoom: 4x optical plus 4.1x digital = 16.4 total -- (10x plus 3.2x = 32x total)
• Continuous shooting: 2.0 frames per second, up to 14 frames -- (1.3fps, unlimited)
The G6 has 2 more megapixels and is 2/3" narrower than the G5.
Some G6 features that the S1 lacks:
• ND8 neutral density filter that allows slower shutter speeds in bright light.
• AutoFocus assist lamp
• Hot shoe for external flash.
• Backlit control panel.
• Save in RAW format.