I'm not much of a backlight person, but I don't mind if a keyboard has lighting as long as it's not blue. Those things are way too bright regardless of the set brightness, and I already have to cover up all the other blue LEDs manufactures are shoving into stuff for power/status indication as is.
On the opposite end, amber and red are really nice and subtle. Not retina burning at all. And with white, you can use plastic covers to change them so they're quite flexible. If a board I found an interest in just happened to be backlit, those would be my color choices, in that order.