I have a 920, and I was going to go with yellow, but it was unavailable at the time so I went with black. I guess it was a good thing I didn't go with yellow since I didn't want to bring too much attention to myself / my phone. Also, the black goes well with all the tile color schemes, so keep that in mind when selecting a color.
I was also considering red, but it looked really cheap and tacky in person.
Whatever you go with, make sure to get a cover for the back because the back can scuff and scratch.