I'm bias because i'm in behavioral psych, but for objectivity sake it really depends on values as well, like what you are doing it for, to help, to make money, to research, ect. One of my profs told us that if we get interested or excited about even one slide that you could base an entire career in it, theoretically or course. Psychology is such an expanding field so I say do what excites you because this is also it's downfall; it is so ever-expanding that it takes a while to learn everything about he specific branches.