Golok, I'd suggest you collect what you like, that way, you'll never feel like you've wasted your money. Essential is personal. Look through a knife guide (Levine's Guide to Knives, 4th edition, is probably the best) and choose the patterns that you think are cool. Once you get a few examples, you might find a particular brand, handle material or some other area to focus on.
I started out all caught up in the latest, high-tech, trendy knife of the moment. Old knives just struck me as someone's toss-aways until I attended my first knife show and got to talking with collectors and seeing their stuff. There is a whole new world to explore collecting old knives, you'll never stop learning about the rich history and high quality of early knives. The best part is the quality of people you'll meet, especially if you have access to a local knife club or knife show.
I'm not putting down new knives, they are the state of the art as tools and I've got more than my share of customs that I consider works of art. There are some incredible craftsmen/artians who are raising the bar everyday. Many are making beautiful reproductions of old patterns. If I were rich, perhaps that's all I would collect. That's another bonus of old knives, you can afford them for the most part. The search is 3/4 the fun and when you've got a beautiful old survior or used up old user in your hand, your holding onto to some history and a part of someones life. Old knives are very satisfying, good luck.
