Pew recently conducted a survey on the matter, but the results they give are a little confusing. Here is a summary created by someone else which presents the pertinent information nicely:
* 36% of white evangelicals think Jews can go to Heaven.
* 61% of white mainline protestants think Jews can go to Heaven.
* 37% of protestants at historically Black churches, think Jews can go to Heaven.
* 61% of white Catholics4 think Jews can go to Heaven.
* 15% of white evangelicals think atheists can go to Heaven.
* 38% of white mainline protestants think atheists can go to Heaven.
* 39% of white Catholics4 think atheists can go to Heaven.
* 20% of white evangelicals think Muslims can go to Heaven.
* 46% of white mainline protestants think Muslims can go to Heaven.
* 34% of protestants at historically Black churches, think Muslims can go to Heaven.
* 49% of white Catholics4 think Muslims can go to Heaven.
* 43% of white evangelicals think Catholics can go to Heaven.
* 64% of white mainline protestants think Catholics can go to Heaven.
* 41% of protestants at historically Black churches, think Catholics can go to Heaven.
* 66% of white Catholics4 think Protestants can go to Heaven.
Source: Alas, a blog
As you can see, most people continue to hold to the orthodox belief that atheists are going to hell. In fact, fewer Christians of every type think that atheists can go to heaven than they do about any of the other non-Christian groups asked about. It's only to be expected that most Christians believe atheists are going to hell, but the belief that you, as an atheist, are going to hell is not a morally neutral belief.
Saying that atheists are going to hell isn't like saying that you'll be going to work in the morning. It isn't even "merely" a belief with serious implications, like saying that unless you stop smoking you'll get cancer and die early. No, saying that you will go to hell because you are an atheist is more like saying that you will go to the electric chair because you're a child murderer but worse.
A Christian who adheres in any way to traditional, orthodox doctrines about hell must believe that people who go to hell deserve to go to hell. They must believe that the people who go to hell should go to hell and that their being in hell is a good thing. Not being in hell would be a bad thing, like a child murderer going free instead of being punished.
There's no reasonable way to believe that people go to hell who shouldn't and that spending eternity in hell is an immoral, unjust situation (like Jews going to concentration camps). This would entail believing that God has set up an immoral, unjust afterlife and no devout Christian would be willing to adopt such a position. So, when a person sincerely believes that you will go to hell simply for being an atheist, then they must believe that you deserve to suffer immeasurably and unimaginably for all eternity. They must believe that it is good for you (and all other atheists) to suffer immeasurably and unimaginably for all eternity.
These implications all follow necessarily from the doctrine of hell, but what follows from these conclusions? To put the issue more bluntly: are such beliefs at all compatible with truly respecting you? Can a person really, truly, and sincerely respect you if they sincerely believe that you deserve to suffer in hell forever simply because you don't believe in the god they believe in?
Personally, I doubt it. If s Christian thinks they can sincerely adopt both the positions "I respect you" and "you will go to hell as an atheist," they're seriously mistaken. These two positions can only both be held if a person completely ignores one while focusing on the other. They are incompatible and one will have to go, even if the person doesn't recognize it yet. Perhaps there haven't been any situations which force the tension between the two to be obvious, but it will happen eventually.
In the long run, though, I don't think that a positive relationship can exsist between two people if one holds on to the belief that the other deserves the same fate as Adolf Hitler and Ted Bundy (or worse, since we don't know if they repented and converted just before death). Remember this when people complain about atheists who are being "arrogant" and "intolerant" for treating theism as a delusion ó it's far, far worse to say that a person deserves to spend eternity in hell for disbelieving in gods than to say that believing in gods is irrational, unreasonable, mistaken, or even delusional.
And what about all the Christians who don't believe that atheists will go to hell? This probably encompasses a large number of liberal Christians but even given their liberal theology, why are they denying a central, orthodox Christian doctrine? There is a little bit of support for the idea of universal salvation in the New Testament, but it's not very strong and that's why it's never been a position with a lot of support in the Christian community. If a atheist who lives a good life isn't barred from heaven, what's the point of Christianity?