I have been using Eagle Creek packing cubes for years to help save space and keep my gear organised when I travel. They are an essential part of my kit. Being the Tom Bihn fanboy that I am I thought it worth mentioning that they have recently released their own packing system. It designed designed specifically to work within the compartments of the Aeronaut but I can’t see any reason to purchase them for use in any bag.
The Packing Cubes are available in four styles: Small (Fabric/Mesh $15), End Pocket (Mesh, $15), End Pocket (Fabric $15), and Large (Fabric/Mesh $18).
Available direct from Tom Bihn.