For the definition of a knife I fall back on the Japanese standard of anything shorter than about 12". Further, the ideal fighting knife without regard to carryability or utility. With that boundary, I offer the fighting bowie as the best fighting knife with the Black Cloud Knives fifth generation Fighting Bowie being a good example:
The Mad Dog Panther is another.
The characteristics of what makes it so have been very eloquently stated by MadPoet, and I quote him from the Knifeforums General Forum (without permission, doh!):
"...the ideal fighter, beyound being a fairly large knife, say at least a 6-7" blade should also be light, fast, and scary sharp. Secondary in importance is strength, or edge retention, or utility as some other kind of survival tool. Taken to the etreme you are looking for something that is going to do its darndest to cut flesh, and afterwards you can worry if it needs to be resharpened!
While handle styles and guards and even the choice of a single or double edge come into play, its the quickness of the knife in use that makes it a great fighter. You don't need an absurdly thin knife, but a stick tang or tapered tang, and blade that is tapered from the hilt to tip reduce weight, and lend to making a longer knife that is still fast in the hand. A high, thin, tapered flat grind and thin, thin, thin, convex edge does the cutting."
[This message has been edited by Steve Harvey (edited 18 December 1998).]