Like some have said, the friendships I have made are more important to me than any knives I own. A friend of mine, who had accumulated many guns over the years and has since pared his collection down, laid it out like this. A good centerfire semi auto pistol, .45 or 9mm. A good rimfire pistol, preferably .22. A good .22 rimfire rifle, and a good centerfire rifle (.30-06 or .308), both bolt actions or lever actions, whatever you want. A good pump 12ga. A single action wheelgun, and a D/A wheelgun. Calibers are of course, your choice. Basically, all anyone would need.
So, I look at knives like this. Everyone needs a SAK or multitool. KISS method for this one. A good folder with a three inch blade, locking/slipjoint, whatever. Everyday carry. Then, a good folder with a 3.5" blade, for working with, when you can't carry a fixed blade. A good camp knife, maybe in the 6" to 9" blade range. A good fixed blade to carry for EDC, fishing, bushcraft etc, 3.5" to 5", 5" is pushing it. Maybe a nice folder for dress carry. Like the guns and calibers, whatever steel you are comfortable with for your knives. Right now, what few I have left, are mainly S30V, O1 and A2.
Then again, limiting yourself is no fun...