Zip Lock Bags are my ‘Louis Vuitton’ for Travel
– for spill-ables
-receipts
-keys and plugs
-electronic gadget cords
-wet washcloths if you bring you own to non washcloth areas like Europe
-socks and underwear
-cosmetics
-snacks for hotel munching
-hair baubles
-medicine
-and for everything larger I use Eagle Creek bags. And always carry a hefty bag for super wet clothes or ground cover or even a hideous but useful raincoat.