To me, there's no one colour that's universally best. It's all about what works on specific bikes. I'm not buying an RS in lime green, but if I'm buying a Kawi sportbike, green is the only reasonable option.
Sportbikes generally work best in company colours for me. Kawi? Green. Suzuki? Blue and white. Yamaha? Blue (or yellow if going for a retro look). Honda? Red and something else. Ducati? Red, natch. Aprilia? Black with a contrasting colour, possibly purple. BMW? Primarily white with blue and red accents.
Aside from the RC30 (far and away the GOAT paint scheme already mentioned here), special schemes for me include:
- 2020-2021 Africa Twin in similar colours (the new one seems to have supersized the logo, which is awful)
- Any special edition RSV4, especially the black one with tricolore trim or the one in white or silver with the big capital 'A'
- any of the retro-styled R1's with the speed block stripe in yellow and black or white and red
- ZX-7R in green (obvs) with the white number boards
- VFR800 in Rothmans colours
- 916 monoposto in red with the white number boards on the tail
- Ducati Paul Smart with the metallic teal frame and silver bodywork
- OG GSX-R750 with the three shades of blue
- last but not least (for me) the CBR1000RR in blue and yellow