SAK (for me: Alox Farmer)
Buck 110
Multi-Tool (Vic SwissTool or Leatherman Wave)
Fixed blade for an outdoor belt knife (BRKT Gunny or BRKT Bravo-1 or RAT RC4 or Fallkniven F1)
Modern Locking one-handed opener (Ritter Mini-Grip)
If I were allowed 6, I'd also say a custom of some sort (NWA Sierra scout for me so far, but that's more of a semi-custom I guess). I think once you branch out into designing and having a maker build your own knife, knife knutness goes to a whole new level.