If you can't choose between two colours, buy them both. Wind a double helix and you have candy-striped handlebars.
And a spare pair of rolls of tape.
Alternatively, put one colour on the left side, and the other on the right.
Or one colour above the brake levers and the other below.
Or a combination of the above.
Or just stick with black if that's too many choices for you. Goes with anything... doesn't show the dirt... boring as hell.