Everyone has different vision and tastes so there really is no "best" other than what is best for you.
I prefer vivid with a bump toward warm. It looks crisp and colorful but is easy on the eyes for prolonged use. Cold colors look impressive but can be irritating over time.
I have it on sRGB because I find I can see the screen better in bright sunlight with that setting. Reading this topic, perhaps I should play around with tweaking to see if I can improve sunlight performance even more...