There has been some talk about a black one maybe coming later, although with Samsung you can not trust "coming later" and they may only be random rumors, nobody knows...
My personal guess is that when/if a 64GB model is released at some point, it will come in black.
That's just me playing the guessing game though.
I was going to get the white one, but I ended up getting the blue in the end. I believe in the likes of Gsmarena when they say that it does look quite nice in person, and not at all like in the official press shots.