Are they the same color? What do you plan on using your phone for primarily? That could determine which one is the one to go with. I'm using mine for photography primarily, which is why I kept the 128 instead of going back to the 64gb.
Yup, both space gray regulars.
I'm a college student (chemist). Let's see... I keep usually about 10GB of music with me, I sometimes use Garageband for tinkering. But the rest of my stuff would be apps (mostly productive stuff, and 1 or 2 games for passing time), iWork and stuff just to do work. Don't take a ton of pictures.