I don't think so. Usually their beliefs are rather benign, and don't come up in conversation very often, because of their irrelevance to reality. And when they actually do have a bearing on their action or their models of reality, it's almost always far better to talk about the issue directly, and discuss their religious beliefs only within that context, so as to keep the discussion grounded, and avoid floating into ridiculous abstractions and word-based meandering.
If anyone ever brings up religion to me outside of a context like that, I just engage in the simplest, most charitable-sounding word-reductionism possible, by asking them what exactly they mean by some word, and whether we're talking about a physical object, or a bodily sensation, or what, or what the utility of their beliefs are, or whatever. It takes a decent amount of practice to do well, but when done correctly it diffuses the situation really quickly and doesn't destroy relationships.
It must also be emphasized that not all professed beliefs are actual "beliefs" in the literal, epistemic meaning of that word. They're not always models of reality that are supposed to predict certain things or whatever. Often they're just techniques for signaling group affiliation, or for avoiding destructive negative emotions (due to some oddity in human brain design), or whatever. Even the word reductionism I explained above may be nothing more than annoying pedantry, and literally off topic, if you're dealing not with an epistemic belief, but with something else (which is perhaps usually the case). To be clear, I use that technique not because I think it's on topic, but because I've found it to be a good firewall technique to avoid epistemic hazards to my own belief structure.
I recently learned that a friend of mine, and a long-time atheist (and atheist blogger), is planning to convert to Catholicism. It seems the impetus for her conversion was increasing frustration that she had no good naturalistic account for objective morality in the form of virtue ethics; that upon reflection, she decided she felt like morality "loved" her; that this feeling implied God; and that she had sufficient "if God, then Catholicism" priors to point toward Catholicism, even though she's bisexual (!) and purports to still feel uncertain about the Church's views on sexuality. (Side note: all of this information is material she's blogged about herself, so it's not as if I'm sharing personal details she would prefer to be kept private.)
First, I want to state the rationality lesson I learned from this episode: atheists who spend a great deal of their time analyzing and even critiquing the views of a particular religion are at-risk atheists. Eliezer's spoken about this sort of issue before ("Someone who spends all day thinking about whether the Trinity does or does not exist, rather than Allah or Thor or the Flying Spaghetti Monster, is more than halfway to Christianity."), but I guess it took a personal experience to really drive the point home. When I first read my friend's post, I had a major "I notice that I am confused" moment, because it just seemed so implausible that someone who understood actual atheist arguments (as opposed to dead little sister Hollywood Atheism) could convert to religion, and Catholicism of all things. I seriously considered (and investigated) the possibility that her post was some kind of prank or experiment or otherwise not sincere, or that her account had been hijacked by a very good impersonator (both of these seem quite unlikely at this point).
But then I remembered how I had been frustrated in the past by her tolerance for what seemed like rank religious bigotry and how often I thought she was taking seriously theological positions that seemed about as likely as the 9/11 attacks being genuinely inspired and ordained by Allah. I remembered how I thought she had a confused conception of meta-ethics and that she often seemed skeptical of reductionism, which in retrospect should have been a major red flag for purported atheists. So yeah, spending all your time arguing about Catholic doctrine really is a warning sign, no matter how strongly you seem to champion the "atheist" side of the debate. Seriously.
But second, and more immediately, I wonder if anybody has advice on how to handle this, or if they've had similar experiences with their friends. I do care about this person, and I was devastated to hear this news, so if there's something I can do to help her, I want to. Of course, I would prefer most that she stop worrying about religion entirely and just grok the math that makes religious hypotheses so unlikely as to not be worth your time. But in the short term I'd settle for her not becoming a Catholic, and not immersing herself further in Dark Side Epistemology or surrounding herself with people trying to convince her that she needs to "repent" of her sexuality.
I think I have a pretty good understanding of the theoretical concepts at stake here, but I'm not sure where to start or what style of argument is likely to have the best effect at this point. My tentative plan is to express my concern, try to get more information about what she's thinking, and get a dialogue going (I expect she'll be open to this), but I wanted to see if you all had more specific suggestions, especially if you've been through similar experiences yourself. Thanks!