World Travellers like to document their trips. A “Rugged” or underwater camera, depending on the trips they're currently planning, is always a great gift. Other than that, it depends on the person. Are they going to Italy in March? Then an english-italian dictionary is a gift that tell them that you remember their plans, and you want to help out. World Travellers are always going somewhere, so giving them something to remind them of home is always a welcome gift as well.