Darrel Ralph. Super designs, super materials, super craftsmanship, super guy. He is my favorite mostly because a couple years ago he set out to make the best using folder you can get, and he succeded. All his designs are functional, ergonomic, and have a personality unique to each knife. Another reason he is my favorite is because he is making a bunch of us what will undoubtedly be the coolest balisong ever.
Second mention goes to Ernie Mayer of Black Cloud Knives. What Darrel is to the folder, Ernie is the the fixed-blade fighter. His designs are innovative, unique, superbly functional, and have a design sense that is organic, exotic, even slightly flamboyant without being flashy or in any way imparing function. His knives handle better than any others I've tried. I own about a dozen of them or so. Love 'em all.
David Boye. Best cutting knives I know of. Again, the superbly functional designs with an earthy design sense. Boye Dendritic Steel is unique, stainless, supreme wear resistance, as beautiful and unique as Damascus. Teamed with Francine Martin of the Boye Knives Gallery you can get a fantastic cutting tool etched with a beautiful design, customized to make it one of a kind.
Kevin McClung. Extremely durable, functional, and ergonomic. Mad Dog knows what he thinks makes a great tactical knife, and I am in very strong agreement, especially in 3/16" thicknesses. His combination of fully enclosed composite handles, differentially hardened tool steel blade, and precise ergonomics make them some of the best and most durable cutting tools available.