Terath Ninir
Yog Sothoth loves you
Another gamer suggested an interesting tweak to nonlethal damage: Starting at -1 hp, the character no longer takes non-lethal damage but begins to take lethal damage.
Thus, if you beat a character to 3 hp with your fists, he takes nonlethal damage. Hit him again and knock him to 0 hp, he's still only taking nonlethal damage. Hit him again with a nonlethal attack, though, and the damage becomes real damage.
I like the idea, but I think it makes it too easy to beat someone to death.
Need to find an idea somewhere in the middle, where nonlethal and lethal damage can occur from nonlethal attacks, but where neither type of attack is overemphasized.
I've played Exalted for years now. Their solution is similar to this, but elegantly simple. You do nonlethal damage (they call it bludgeoning) until they're down to 0. Then it becomes lethal damage. It's quite simple and even passably realistic, if you care about such things.
As for the original poster: bad guys and Jack Bauers are always reviving unconscious people in stories and then beating on them some more. Just come up with a heal DC you can live with and have the revived character be stunned and mostly unable to act.
Added bonus advice: if you play a spellcaster in 3.0, take the Subdual Substitution feat. It doesn't increase the level of spells you cast and converts the damage from its original type to subdual damage. You can wipe the floor with Outsiders after that. Are demons immune to fire or just resistant? Who cares! My subdual fireball will knock it out and then we'll coup de grace it. Note that they figured this trick out later and Nonlethal Substitution is nowhere near as cool.