Military experience would be valued b/c it is a great career to have, not an extracurricular. You are serving as a leader and fighting in a war. Ability to stand up in the face of adversity is a pretty good quality.
As for extracurriculars, I would target things that match your profile or story. As an example, I was inspired by a teacher in undergrad to take up a writing/rhetoric minor as a business major which was fairly uncommon. I parlayed my love of writing into tutoring and volunteering at a writing organization for middle and high school kids.
I would say that there are certain extracurriculars that are better than others, but follow what fits for you and don't do something b/c you think it looks good. Big Brother/Big Sister is really popular and pretty much everyone I know that got into an MBA program did this at some point. It's not about the quantity either, quality and leadership experience are important.
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