I'm not so much of a collector as a user. My advice is to go slow and pick a few good value high quality knives with different types of locks, handle materials, blade shapes, or steels, so you can begin to determine what you like. I go through phases: aluminum handles, frame locks, titanium, sheepsfoot, little big knives, etc. and I like them all. I always recommend starting with the Spyderco Delica/Endura series and the Benchmade Griptillian series, are good values with enough variety. You'll find a some others that are very popular on these forums for good reason. Once you determine your true favorites, you can start to collect a series of that type, style or brand. I personally, haven't gotten to that point yet.