It has been just 16 months since Rob Bell's Love Wins was released. The book, which seeks to undermine the biblical doctrine of eternal punishment, was roundly rejected by evangelical leaders (see here, here, or here). But in college ministries across the country, it had the effect of introducing ambiguity where there was previously certainty.
Today, Rob Bell has left his church, and moved to Los Angeles where he is "working on other creative projects," and thus proving Jesus' words that wisdom is vindicated by her children. Those projects are as of yet undisclosed, but there are rumors of a TV show about his life.
As for the theology about eternal punishment, I don't know of any churches that have changed their doctrinal statements as a result of Bell's book. He may have introduced ambiguity into the hearts of Christians, but-as of now-it seems like the doctrine of eternal punishment withstood its latest attack.
It is helpful to remember why Christians believe in eternal punishment. I'm not talking about the theological reasons, of which there are many. I'm talking about the biblical reasons. This is a doctrine that is so horrible that nobody would accept it or teach it willingly. It takes more than deductive reasoning to get people to embrace the concept that the majority of people who have ever been born are now in hell, and that they will be there forever. As Robert Peterson in Hell on Trial points out, there are really two kinds of Christians: those that have entertained doubts about the eternal nature of hell, and those that have not seriously thought about the implications of the doctrine. Even Wyane Grudem points out that "if our hearts are not moved with deep sorrow when we contemplate this doctrine, then there is a serious deficiency in our spiritual and emotional sensibilities."
Because of the reluctance with which most people hold this doctrine, it is not as if the arguments that are put forward in Bell's book are going to be persuasive. If sound and biblical thinkers could be persuaded out of believing in hell, they would abandon the doctrine. Most people who hold to the doctrine do so not because they want to, but they have simply been overwhelmed by the biblical evidence. For me at least, this is how my thoughts go: "I don't want to believe in hell, and I can't imagine the horrors of it, and I can't imagine how and why it would endure forever and ever, but the Bible is so clear that this is the case, and I am bound to believe what the Scripture teaches."
What are the main Scripture passages that describe hell as eternal? This list is not comprehensive, but are the ones that I think are most clear:
 OT Prophecy: The most well known passage in the OT on hell is at the end of Isaiah. There, the prophet describes hell as being visible in the eternal state, and notes that "Their maggots will never die, their fire will never go out, and they will be a horror to all mankind" (Isa 66:24). The context of this passage is important. Isaiah is describing how at salvation, the old is gone and the new will be there (Isa 65:17). In that place, where people dwell with God forever, the torment of hell will be real and ever present. Then, to seal this imagery, Jesus quotes these words in Mark 9:48, using the Greek word that indicates that this fire is indeed eternal. Daniel describes hell as eternal as well (Dan 12:2), and this is another verse that is repeated by Jesus.
 Jesus: Our savior describes the fire as hell as "unquenchable" (Mark 9:43). He describes hell as eternal when he explains that at final judgment he will say to those on their way to hell "Depart from me, you who are cursed, into the eternal fire prepared for the Devil and his angels!" (Matt 25:41). Later he compares the eternality of hell to the eternality of heaven (Matt 25:46).
 NT Prophecy: The Apostle John describes the smoke of hell as ascending "forever and ever." In that same passage (Rev 14:11) the smoke is explicitly connected to the torment of those suffering, and is then compared to the endurance of the saints. So the torments of hell last as long as the endurance of those who are saved. This imagery is repeated later-and applied to demons and the devil as well-in Rev 19:3 and 20:10. Later in Rev., it is clear that throughout the new heaven and new earth, there are those outside the city who are being punished by torment (eg. Rev 22:14), so that as long as heaven exists, this description stands.
At the very least, the Bible ties the duration of those that worship God to the duration of those that are punished in hell by God. It is not a happy truth, but it does continually provoke us to be more thankful for his grace and mercy, and that thankfulness will apparently grow even throughout eternity.