Saying the A340 needs winglets to squeeze extra performance is mean and also wrong - as Ben88 says, it's the best wing in the business. Fact. And what's this about the A300-600R? It hardly has winglets, just little fences to stop clumsy mechanics falling off the ends of the wings (hoho). If you want to talk about winglets being added to old wing designs, Jet Setter, have you heard of the 747-400?
The first commerical aircraft with winglets were Learjets, and they have great, highly efficient wing designs that were ahead of their time. It has nothing to do with fixing an inefficient design, it's making the whole wing work and depends upon many factors.
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz