New SGS owner here (just got it Nov. 10). OK, I know an SD card gives you extra memory for media files, but since the phone comes with 16GB is it really necessary? The basic iPhone 4 comes with 16GB and I don't think most users are clamoring for more. Does it help the SGS speed if you leave most of the internal memory free (only using it for apps) and use the external card for all your files? Or does it just provide an opportunity to go crazy with storing files, like an entire season of a TV show for instance? All that being said... yes I did spring for an 8GB SD card but is it money well spent... who knows.