Without thinking too much, I'd have to say my "best" knife is my Vic Soldier. It will probably be more useful, and perform as well as any other knife I own, on a daily basis. It's near and dear to my heart, although hardly anything to write home about (although apparently not so bad that I won't write about it on this forum).
My favorite is a tie between my medium amber bone stockman with CV blades, or my single blade queen trapper (or utility knife) with honey bone scales and a D2 blade. If I had to choose one, I might pick the Case just cause I've carried it about 5 years longer. A new favorite might be the Northwoods Scagel #11 my girlfriend just got for me, but we (meaning the knife and I, not the girlfriend and I) haven't had time to bond yet, so I'm not ready to give it the nod just yet.
I love these forums! This was fun.