There are few things worse than picking up a book and trying to muddle your way through a boring/unlikable narrator. You could have the greatest story in the world, but it will all be for naught if your reader is trying to figure out why we're following Judith Day around because she's so bland, boring, and/or annoying.
A lot of new writers think that only First Person stories have an actual narrative voice. It's in First Person that you're trapped inside the character's mind and have to conform to their view of life and reality, so the person talking had better be very interesting. The problem is, it isn't just First Person narratives that have a voice. ALL points of view are written in voice, either by the voice of the character or by the voice of the omniscient narrator, there is always, always, ALWAYS a voice.
In a Third Person story, especially in a very distant or omniscient third, the narrative voice is a reflection of the writer. It gives us the impression of someone looking down and relaying events that he or she is seeing, so we often get opinions or observations that the characters couldn't possibly have because the narrator can look into every mind and situation and lay it bare to the audience. These narratives, however, are rather rare and are most often used for satirical commentating.
Closer Thirds behave more like First Person and reflect the mind of the view-point-character. In a really good Third Person narrative, you should, in theory, be able to switch all the character tags from he/she/him/her to I/me/my without any confusion, contradiction, or POV violations.
More will follow on Voice and Narration, but for now, check out the Links page where you'll find Character and View-Point by Orson Scott Card. As an author, I swear by that book.