I use Bluff for taunting, opposed by Sense Motive, but I only allow it to work against Chaotic or undisciplined opponents. Goblins, gnolls, and the stupider giants can be taunted, but most human-types are too smart to fall for such an obvious trick.
Think about it. You're Joe NPC, standing shoulder-to-shoulder with your comrades, fighting very dangerous opponents. You're mainly worrying about the tall guys in plate armor and the fire-chucking wizard. There's also a skinny dude with a guitar, standing off to the side, whom you're ignoring because he isn't trying to kill you. If that guy starts talking trash about your mother, are you going to turn your back on the fighter and charge straight over there? I don't think so.
If the party ever insists that all opponents be susceptible to taunting, I'll allow it. But then the bad guys get to do the same thing. After the fighter gets taunted into charging a storm giant, and the mage gets taunted by a bad guy with a Ring of Spell Turning, I'm sure they'll change their minds.