I think everyone in this thread that is talking about the 16gb is right, it will be enough for THEM and YOU
But for me, not even close. I am coming from a 64gb iphone 4S that i filled up easy and had to stop buying games. When you download games like Infinity Blade 2, Modern Combat 3, NOVA 3, etc and each is 2gb+, you use up the space fast.
You can't just assume all quality games are the same size as angry birds lol. Angry birds is like 20-35mbs because it's a VERY SIMPLE 2D game. Once you start downloading 3D MMO or FPS then you will use space fast.
So yeah, if you aren't a gamer, the 16gb is PLENTY. If you are, it's not. Now if you COULD move any app data to SD, it's fine. Just keep buying 64gb micro sd cards. But i keep reading you can't move your apps to sd on SGS3 which sucks. Oh well, we'll figure it out when we get ours