Depends upon the type of shooting you are doing:

There is shutter lag, which is the delay between the time you press the shutter button until the photo is captured. All digital cameras have some shutter lag. A shutter lag of 0.1 to 0.3 second is considered fast.

There is shot-to-shot, which means you are shooting two or more photos as fast as you can press the shutter button. A fast speed is about 1 shot every two second.

There is continuous or burst shooting, which requires you to set something on the camera to get into continuous mode. In that mode, the camera will take photos as long as you hold down the shutter button. This is the fastest type of shooting. And a fast speed is about one shot per second.

Then there is flash.
A flash uses high voltage and it take some time for the flash to recharge between flashes. A fast recharge time would be two to three seconds. The recharge time will differ depending upon how fresh your batteries are and how far away your subject is.

The Canon SD780 and SD960 are the among the fastest Canon small cameras.

Here are two links:

http://www.steves-digicams.com/camera-reviews/canon/powershot-sd780-is/canon-powershot-sd780-is-review-2.html

http://www.steves-digicams.com/camera-reviews/canon/powershot-sd960-is/canon-powershot-sd960-is-review-2.html

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