Since Canon lists the camera as SD/SDHC compatible it doesn't matter. SDHC comes in higher capacities, but for the small file size in your camera its not necessary, and probably undesirable. The more files on the card the more images to be lost if card malfunctions or gets misplaced.
"The more files on the card the more images to be lost if card malfunctions or gets misplaced".
And with that said, do yourself a favor and when you get home copy all your pictures to another source. Don't ask me how I know. 
