You can pick and choose and most of my students who seek ACGME residencies will do Step II. By the end of OMSIV, most students anywhere have learned the same things (the doing of Medicine, rather than the knowing of Medicine) and so handle Step II very well. At least mine do.
Step II and III are more outside my expertise, so trust residents and senior medical students, plus your Clinical Dean's' advice on what to take and when for the higher level Step exams.
One more thing, it also seems that PDs of the more competitive ACGME residency programs are OK with COMLEX II than with COMLEX I! There's a chart out there somewhere showing this.