What is the best makeup look for platinum blonde hair?

The one you like best, taking into account the time of day, where you're going, what you're wearing and how much experience you have with wearing makeup.

The last can't be overemphasized. I could tell you, "wear MAC Silver Ring and Amber Lights eyeshadow and Brave Red lipstick, it's a great combination for platinum blonde hair." And it would be. But Brave Red is VERY red, and if you just started wearing lipstick it will scare you badly.