Voices can be a tricky thing. I'm playing in a game (DM running Red Hand of Doom) where I play a character that was a sailor who got stranded on a remote desert island when his ship wrecked. There, he discovered a vestige (from Tome of Magic) and made his first pact with it, to get him off the island. Sort of your "deal with the devil" type character. I've since taken sorcerer levels (going for anima mage) so he's become this weird occultist/magician. So, I use an accent that's a cross between the trolls in World of Warcraft and the Rastafarian voodoo witch from the most recent Pirates of the Carribbean movie. His catchphrase is, "Dis XXXX is cursed!" substituting an object, place, or person for the XXXX. So, he walks into an abandoned mansion, and says, "Dis house is cursed!"
My fellow players get a big kick out of it, mostly because it's a non-annoying voice, I use it sparingly, and it's become kind of a running gag.
On the other hand, I also play in a bi-weekly game where a player is playing a low-Charisma fox person. The first few sessions, he used this whining, simpering, awful voice that was a cross between Igor from the old black and white Frankenstein and Pat from the "It's Pat!" sketches on Saturday Night Live. Needless to say, about 20 minutes into the third session one of the other players jumped up and begged the player never to use that voice again. "Yes, we get it, low Charisma, but just make my ears stop bleeding!" Bad part was, this came from the most mild-mannered and normally live-and-let-live player in the group. Fortunately, the other player has since ceased using the horrific voice.
Another player likes to use voices, but unfortunately he only has two. No matter what character he is playing, he only uses one of two voices. The first, which I've dubbed the paladin voice, is the bellowing, blustering, take-charge and the hell with the consequences kind of manly-man voice. He starts every sentence with a barked "Right!" and it sounds a lot like Gaston from Disney's Beauty and the Beast. The other voice is his soft-spoken voice. He uses it for females or diplomats. It's very quiet, very effeminate, and almost otherworldly. Also, very condescending. In his defense, he's also come up with a third voice -- his own -- which he is using for the bard he is playing now. It's the best one.
So, yeah. Voices can be a double-edged sword.