statistics can be another minor that can give you that edge when trying to get a job. If you want to get an mba than most of the ivy/top10 schools suggest doing a minor in something not related to your field of study. Possibly adding poli-sci minor, global studies minor, history minor will help you when applying to mba programs. Look at stanford's mba admission page. Of course Double majoring is probably the most compelling but in the end were you can get the highest GPA is of the most importance (for mba).
If your a sociology major with a 4.0 and everything else is identical to a econ major with a 3.0 the sociology major would get into much better mba schools (assuming everything else is identical gmat, ect). In fact the majority of mba programs are composed of students from undergraduate studies in areas other than econ and business at the top schools. Oh and get good grades in your math courses!
