For those of you with the big expandable briefcases, what do you stuff in 'em?

I'm about to blow some $$ on a higher end briefcase and am deciding what size to get. I've only really needed to put a laptop, some chargers, and a set of headphones in my briefcase. However, I often see people hauling large bags along with their carry-ons and wonder if I'm missing out on stuffing more in there?