Imho for self defense to apply you should not technically "fight back". In many countries self defense is about stopping the fight and getting away from danger as quickly as possible. That means either (1) running like hell in the first place or if this is impossible because it is an ambush (2) dropping the guy in 3 moves or less then proceeding to step (1). (Generally a much more dangerous option as well)
Imho no circumstance prolonging an altercation by fighting back over a long period of time can be called self defense.
www.nononsenseselfdefense.com [This message has been edited by Leo_E_49 (edited 03-10-2005).]