It's hard to pick only one, but I will have to go with my orange Pack Rat. It is the first Kershaw I bought, and an excellent example of new/different design and quality craftsmanship. Now I have trouble counting how many other Kershaws I have, but this is the one that started it all. A close second is a very used DWO with a broken tip that is my son's first knife - it's perfect for cutting green beans and carving sticks, and hopefully will stick with him for a long time.