Depends on the person. My must have apps change but they usually fall into the same categories. I have to have my banking and credit card apps. I need some form of PDF scanner and either the ability to annotate or another app that can annotate. Some form of to do list app, though I have been using clear+ for a while because of simplicity and I like the gestures it uses. Other than that, I like to have a time waster, which is usually a game, crunchyroll, Hulu plus, or Netflix.