Your 83xx can read SD and SDHC cards alike, it all depends on the size of the card (cards bigger than 2GB are SDHC).
Basically it's preference. 4GB is the biggest size that can be read by OS 4.2 though iirc, allthough you might wanna think about buying 8GB if you're speculating on OS 4.5 being able to read 8GB.