I asked my guide at the Neckarsulm factory which colour combination he thought was the best, as he sees every car that comes off the line.
He was unequivocal. "The White with the Black Blades is by far the most beautiful, in my opinion". I was happy to hear that, as it was what I had already ordered.
White cars are also the easiest to keep clean and looking great.
I have seen an all-black R8 and must admit, however, that I thought it looked fabulous, so whichever you choose will look fantastic.
A Canadian test driver said in his writeup that of all the exotics he has driven, the R8 V10 in white with black blades drew by far the most attention. Not sure I want that, but it is a pretty good indicator of how beautiful the car is.