I'm thinking that if I get an M5 I don't want it to be black. It also can't be too loud. My wife doesn't like Marina Blue either.
Aside from interesting colors like Ermes Verde, I'd probably prefer Donington Grey, which is the closest to silver they have. I don't like the darker grays.
For the sake of not waiting for a unicorn I may have to be open to Aventurin Red and Tanzanite Blue.
The easy find would be white which is not so bad considering the dark CF roof, but we already have the white GTI and it is not easy to keep clean. I'd rather avoid it.
Also, this whole discussion assumes a Competition M5, which is by far the most common, but a base M5 may be better in many respects. They are harder to find but not impossible.