With its straight sides and boxy frame, the classic leather-clad hinged briefcase carried by "Mad Men" and James Bond wannabes alike was designed to protect papers such as lawyer's briefs, for which this piece of everyday luggage was named.

Briefcases with flat bottoms and flexible sides that fold over the opening at the case's top can be packed to overflowing, while still staying upright when set on the floor. The heftier pilot's briefcase features dividers and pockets inside, while the flexible, handleless portfolio is only as rigid as the stiffest thing it's carrying. These days, that's usually a laptop.