I've decided to stick to SD format (up to 4Gb size, but I'm primarily using 2GB micro SD cards in order to format them in FAT16) because it's backward compatible with SDHC, and because some older devices may not be able to deal with SDHC cards at all.

Also consider the impact of loosing the 16GB of data on SDHC card versus just 2Gb on SD

Or you mean the SD card form-factor versus micro SD?