I can't give you the actual specifications, but having just picked up a G10 this week, I can say that it the shutter lag is practically non-existent. If you fully depress the shutter, the shutter releases as soon as the auto-focus is acquired (slight delay depending on the ease of auto-focusing on the subject). If the shutter is depressed half way and focus is already acquired then the shutter release is instantaneous, no perceptible delay.
Shutter lag is not an issue with this camera. I normally shoot with a 5D and the image quality from the G10 at ISO 80 - 100 and f/4 is stunning. I now have a constant companion that can produce exceptional image quality. Go buy one!
I too, use a 5D for my "serious" photography but have been using an old Power Shot 1 for my more casual work. I love the articulated screen on the PS 1 but the shutter lag has been a headache.
Perhaps the G11 or G 12 will reclaim the articulated screen.