Charisma measures a character’s force of personality, persuasiveness, personal magnetism, ability to lead, and physical attractiveness. This ability represents actual strength of personality, not merely how one is perceived by others in a social setting. Charisma is most important for paladins, sorcerers, and bards. It is also important for clerics, since it affects their ability to turn undead. Every creature has a Charisma score.
You apply your character’s Charisma modifier to:
-Bluff, Diplomacy, Disguise, Gather Information, Handle Animal, Intimidate, Perform, and Use Magic Device checks. These are the skills that have Charisma as their key ability. Checks that represent attempts to influence others.
-Turning checks for clerics and paladins attempting to turn zombies, vampires, and other undead.
-Sorcerers and bards get bonus spells based on their Charisma scores. The minimum Charisma score needed to cast a sorcerer or bard spell is 10 + the spell’s level.
-A Paladins Divine Grace, or Knights Challenge.
Unless you are playing a Sorcerer or Bard, this is the most common lowest stat. If you are playing those classes it should be your highest. If playing a paladin or knight it should be one of your higher scores, but not the highest, the 14 range should be fine. If you do not have a class feature based on Charisma, it should be your lowest stat.
For more uses of Charisma, see the X Stat to Y Bonus thread on the WoTC message boards.