Use FMJ only if that's all your gun will feed. Otherwise use of HP is prudent. Gabrielle Gifford was shot in the head with a 9mm FMJ, and shes recovering.
Can't get much better shot placement than that.
Had the bullet been HP instead of FMJ, no way she'd have recovered.
Also, anyone care to speculate on her chances had she been shot in the head with .45 ACP FMJ, instead of 9mm FMJ??
Taste the wares, Email.