I find that Spa Yellow Pearl and New Formula Red (or Formula Red) photograph the best, look great in person, plus they turn heads more quickly as they drive by. Side-by-side, there's no question...yellow will attract your eye first. If you can live with attention, yellow is the color to own. That said, I own red.
In person, a freshly waxed black NSX is hard to beat, but I'd get a Kaiser Silver NSX over a black one. I could easily see myself driving a Kaiser Silver NSX.