Wanted the 64 GB space grey, but that was the only model they didn't have, so I said WTH, and got 128 GB. I'm not sure why it matters, though since I always put a case or a vinyl sticker on, so you'd never know what colour it was.
Was looking for the SG 64GB Wifi, but it was gone by the time I got there. Purchased the SG 128GB Wifi instead. All in, the 128GB was less than the regular price of a 16GB Wifi, so I said, what the heck.
Silver 128GB cellular. I went back and forth a lot on this. I've always gotten black devices, but wanted a change. I love the gold iPhone 6/Plus, but was not impressed with the gold iPad. Ended up with the silver, and I think it's quite striking.