Interesting thread. Most of the gun guys I know are also knife people. Guess that's why the "Gun & Knife Shows" are so popular here in Michigan.
I have a modest collection - accumulation, really, of knives. Mostly folders because that's what I can carry in an urban setting.
Over time, I've accumulated a fair number of good quality production blades. I've found ATS-34, ATS-55, Aus-6, and Aus-8 are the most durable steels, and the easiest to keep sharp. Spyderco (
http://spyderco.com/edge-u-cation/) and A G.Russell Knives (
http://www.agrussell.com/knife_information/knife_encyclopedia/articles/steel.html) have good charts of the various knife-making steels. You don't need a degree in metalurgy, but it helps!
Even after buying the knife I carry - a Spyderco Delica - I continued to buy other, more expensive knives. The store owner told me when I bought that Delica (AUS-8 steel) that I wouldn't be coming back to his store because I just bought the best carrying knife, period. He was almost right. Russell keeps sending those great catalogues and occasionally I bite on a new concept, easy opening, greatest-knife-to-slice-bread-with. After a few days I aways go back to the Spyderco Delica.
I finally bought a second Delica with detachable pocket clip (my original one has a molded-in clip) and made from ATS-55 steel. The original is still fine, but I bought an EdgePro sharpening system from Ben Dale in Hood River, OR.
http://www.edgeproinc.com/ Mr. Dale demonstrated his system to me by sharpening my AUS-8 Delica. It's now one of my treasures and only comes out of the box when I want to shave the hair off my arm!