Hi people, it's confirmed. The SD card should be a class 6. How I know?? Because I called up Canon and checked, and then proceeded to the shop to buy. Upfront the salesperson already tell me frankly it is class 6, so I got it on the spot....
Hope the above helps.
FYI, the difference in price is only about $14 between a class 4 and class 6, both are only normal cards. I called to confirm with Canon as I only want to deal with honest people. If the salesperson tells me bull story that only class 4 is available, I would have walk out. Frankly to me, it doesn't matter whether it is class 4 or class 6, it is the integrity of the person that I care most in any dealings.