Say the chips were down...your life, and everything hold dear was on the line and you had to choose one hero to have your back. One hero to make things right again...
Who would you choose?
And you can make the challenge equal to the means of the hero (i.e. you might not want to choose Batman if Darkseid is sitting in your living room. But you might if it were the Joker, you get what Im sayin'?
) So whomever you choose, they would meet a challenge they were capable of handling.