What if you are taking an Adventure Vacation that involves bringing a significant amount of sports clothing & gear like hiking boots, poles, and backpack with water-bladder, etc.?
Consider a duffel bag with wheels and a built-in telescoping extension handle that pulls out so you can roll it like a suitcase (be sure it is not just a flimsy cloth handle which will make pulling your bag very awkward and difficult).
Preferably the bag is made of tough, durable material with substantial zippers and one or more additional compartments (for boots, dirty or wet clothes or anything you wish to not come in contact with your regular clothing in the main compartment).
A duffel like this will work very well as your only bag if you also purchase packing accessories such as lightweight, meshed folders and cubes (<--click here) such as those made by Eagle Creek.