When I was in elementary school, I had a teacher who was fond of calling certain students "rednecks." Often, he would tell the student that they should "rub the back of (their) neck to get some of that red off!" Notwithstanding the fact that such an action could only serve to make a neck more red, rather than less, it seemed pretty clear to me, even at that time, that this teacher considered "redneck" to be a bad thing. In retrospect, I find myself amazed that he never seemed to get into trouble for these insults.
"Redneck" is not a term I'm comfortable using. I simply cannot think of that term as anything other than an insult.
Not everyone feels that way, of course. I know some people who wear the term "redneck" as a badge of honor. Certainly, Jeff Foxworthy has built his career off of this phenomenon. I don't even know that they would argue for a different definition of the term than my old elementary school teacher. They simply have taken the would-be insult and turned it around into a term of pride. In effect, they seem to be saying, "I am who I am, and I'm proud to be who I am, and anyone who has a problem with that... well, that's their problem, not mine!"
This has happened many times across history, of course. One famous modern example involves the symbols of the Democratic and Republican parties: the donkey and the elephant, respectively. Both were used in political cartoons; the donkey to symbolize the stubbornness of Democrats and the elephant to paint the Republicans as "fat" off of their supposedly ill-gotten wealth. Both parties now use those animal symbols for themselves without any apparent hint of negativity. Another example, particularly pertinent to the blogosphere, is how "Geek" (originally a term referencing someone who bites the heads off of chickens in carnival sideshows) has been used to make fun of people who know too much about particularly focused areas of expertise (especially if related to math, science, or television shows), but which has since been adopted by the geek community with some manner of pride. Some sources even suggest that that term "Christian" started out with derogatory intent.
While I am proud of anyone who can overcome adversity in such a way, I don't mean to suggest that such well-established cases of people rising above names intended to insult them makes the name-calling okay. Intent to insult is still wrong, and whatever people might do to turn things in their favor doesn't remove that negative intent.
I just can't see myself calling someone a "redneck" anytime soon.