John W. Smith.
I would not mind collecting CRK, Tom Mayo, or Strider, but their lines have less variety. Smith does some of the best tactical folders in the world, period, and is known for his art knives. If his tacticals are some of the best in the world, and he is known for his art knives, what does that say about his art knives!?!?!?! He offers a top-tier knife for every occasion.
Darrel Ralph would probably be my second choice. He has a lot of variety as well. He offers balisongs that Smith does not, but Smith does the dress knife thing better.
I think this is not the same as "who is your favorite maker/brand?" because Smith is not my favorite knife maker, but I would rather own all of his knives/models than, say, Tom Mayo, because I feel he offers more variety than Mayo does. As a matter of preference, I think I prefer Mayo's designs a little more.