The drawers are tall enough but they are definitely not deep front to back. That's my biggest gripe about the box. There's not enough floor space inside. My wrench sets are stacked on top of each other rather than laid out.
compare it to the typical setup--not as deep as a snap-on maybe, but way deeper and taller than the craftsman setup I was using before. since I have the top box as well, I have plenty of floor space.
I dedicate a separate drawer for std and metric wrenches and you can get a full set of combo's on one side laid out, and a full set of gearwrenches on the other, with space for other wrenches as well.
check out the black plastic drawer organizer that HF sells for $10. you have to trim about 1/8" off it to fit the drawer perfectly, but it's got spots for the 2 sets of wrenches, spot for allen wrenches, and 3 more spots for stubbies, ignition wrenches, and DBE's. I love mine, but I dremeled out one of the allen wrench spots for more space in each one.(std, metric). you could dremel them both of you don't keep allens in the wrench drawer.
they only ever have one or two in stock at a time so you may have trouble finding it. not a typical china import they buy by the pallet, they may get them locally...which is why they are in-store only.
http://www.harborfreight.com/76-piece-wrench-organizer-46884.html
added pics of how I cut mine.