In my opinion, the Endura 3 and Pacific Salt are the best fighter-folders made by Spyderco.
And here's why:
1. Lightweight enough to always have with you regardless of the attire (yep, even if you're wearing just your underwear).
2. Reliable lock-back design (I just don't trust liner-locks, which knocks the Military out of the contest).
3. Plenty of blade length to get the job done.
4. Rather inexpensive and easily replaced should the knife ever need to be left in the attacker, taken as evidence, or dumped in the river.
5. And the names "Endura" and "Pacific Salt" are more jury friendly than "Military", "Para-Military", "SpyderHawk", or "Police".
In fact, the yellow Pacific Salt would probably be very jury friendly in the courtroom.
The Rescue and the Atlantic Salt are good too, but I think the blunt sheepsfoot tip is too limiting for self-defense.
The waved Endura 4 is also great for self-defense, but it's just a little heavier than the Endura 3.