The obvious answer would be a backpack right? Thats what I have always used in the past, but I'm 35 and my back hurts. During my last trip (ended when I was 30) I remember thinking I need a new pack or something.

Has anyone tried those backpacks that also have wheels? Are they worth a shit? It would be nice to be able to roll my bag in airports or big cities, but also have a backpack for my more adventurous destinations and activities.