I was going to suggest the same thing. I am using a S80 and can get a pictures every 3 seconds. In linux I can get images a bit quicker using libptp by setting the USB packet size bigger, and I have not yet had any problems. (not much of a speed increase though). Also, you can save some more time by doing a focus lock before you begin shooting.
On a side note, I have found that Canon's SDK does not work with the S80, does anyone have any suggestions?