I went Sakhir Orange.
I was worried it would be too bright, but actually I don't think it is. It's unusual, but then so is the car!
I did not want a colour from the Black/Grey/White/Silver pallet, there are so many cars like this around at the moment. Look down a queue of traffic and it's just monochromatic as far as the eye can see. White, in particular, is a colour that comes in and out of fashion, it's in at the moment, in a few years it will be out! My E39 M5 is Carbon Black, it's a nice colour but I wanted something different.
So, apart from Individual colours that just left San Marino Blue and Sakhir Orange (Havana excepted). I did consider Tanzanite Blue, but I think it's a bit dark, on a dull day (and we get plenty in the UK) it almost falls into the monochrome category.
I decided against San Marino just because I'd previously had a LeMans blue E46 and most M5's here are Monte Carlo Blue, but it was very close between the two.