Voiced or unvoiced?
Do you pronounce “moths” with the soft TH, that is to say, the voiced dental fricative as in “then”? Or do you pronounce it with the hard TH, the voiceless dental fricative as in “thin”?
[EDIT: Re-voting now enabled.]
Singular soft, plural and possessive hard.
EDIT: Oops, flip that around, see post below.
What? Wow. That’s completely opposite from me (singular=hard, plural=soft) except for the singular possessive which, like you, is hard for me. Well, I say I pronounce hard, but I might be a bit loose about that. I’ve never really had the need to speak of moths in the plural possessive, at least that I remember, and I don’t even want to think about that right now. I’d have to make some kind of choice for something I could instead talk my way around.
Please remember to vote. Now that I’ve shown my hand, I’ll do that too.
Always hard (singular/plural), struggling with the concept of another way and wondering why I’d need to speak possessively of them or change my pronunciation if I did! 
I realise that speaking of a moth’s wings or antennae isn’t the sort of material that might fall from everyone’s lips, but it’s something to have in your pocket. 
Seriously, I’m still floored by I.D.10-t’s report. I thought everyone - at least in Minnesota - would pronounce the singular with the hard TH.
Ah, that kind of possessive (makes sense now, but still hard)! 
Trying to keep straight the hard/soft terminology is making me crazy. 
It’s voiced (+V) vs. unvoiced (-V) at issue. And if anything, I’d call voiced “hard” and unvoiced “soft”.
Singular always unvoiced. But I’d say the plural voicing is pretty much in free variation for me. Sometimes one, sometimes the other, basically at random.
The same with other word-final th words: sloth(s), Goth(s), bath(s), lath(s), etc. Free variation. Except when the th is in a consonant cluster; then it stays consistently unvoiced: month(s), plinth(s), hearth(s), etc.
It’s like roofs/rooves. I’ll say either. But in this case there’s prescriptive pressure, since only the first spelling is considered “correct” *. Whereas the +V/-V “th” share the same grapheme ever since we got rid of good old thorn and eth.
There’s a strong historical tendency to voice final fricatives in the plural: hoof->hooves, calf->calves, cloth->clothes, life->lives, etc. Whether +V or -V is now correct is a matter of historical accident.I’ve heard that before, but it makes no sense to me, linguist that I am not. How does an unvoiced TH not sound “harder” than the voiced? It baffles me.
I’ve changed the wording of the poll to ensure better accuracy.
But, anyway. I’m basically just asking for a show of hands, with story to follow.
Interesting that you should mention “Goth(s)”. The aforepromised story: Last evening was the weekly Goth Nite - such as it is - at the old watering hole. Naturally these interlopers are often conversational fodder for the regulars, but we all basically get along. I happened to be speaking of them to one of the regulars when, in indicating the plural, the pronunciation “gawðz” came out. Totally unintentional on my part. But I was taken aback by myself, and soon realised that I was reflexively drawing on precedent, such as I knew it but had never really thought about before. I realised I’ve always pronounced bath(s), cloth(s), truth(s), moth(s), and a number of other similar examples - but not all such, of course - in the singular=unvoiced / plural=voiced manner. And I know other people do too, if not all. For the life of me I couldn’t tell you where I got it; it’s just the way it’s always been.
Of course this brought me to Googling, and I note that in Wiki “moths” is attested to be of unvoiced TH. Well, not in MY corral, bucko. Hence the poll.
Story continued: Delighted with my discovery, and knowing full well that the norm for “Goth(s)” would be toward the unvoiced TH whatever the case, I declared to another fellow barfly my intention to henceforth always pronounce “Goths” with the voiced TH as befits precedent, and my own practice. He, being of a more rigid imagination, objected. Of course I expected this; where’s the fun if you can’t push someone’s buttons? I said, “Well, it’s the same thing as the plural of ‘Smurf’ being ‘Smurves’”. He turned purple and objected even more loudly. I then told him to dig into his pocket and buy a sense of whimsy. I mean, jeez. We’re in a bar, fercryinoutloud. 
That is because I got the Hard/Soft pronunciation backwards.
I can say moth as in thin but moth as in then feels weird. The then th helps break up and show the s. No revote, so make a mental note.
Aha, another victim of the terminology.
You may now re-vote. Should’ve installed that earlier.
Just so long as we all know by now what I was intending to mean, right? Minimal damage.
Likewise perplexed by the voiced/unvoiced designation. So, I don’t know if I voted correctly.
But, like others have said: Moth—hard th, moth’s—hard th, moths—soft th.
However, like MT, I do not promise to be consistent.
Always thought that was an odd use of Salvador Dali’s work.
Aha, MTGuru - another voice of common sense in the “hard/soft” TH designation debate.
Emm, unvoiced TH is what you have in “think” or “bath”. Voiced TH is in “this” or “bathe”. To explain more broadly, with any unvoiced consonant there is no voice (or sound from the voicebox) as part of the thing itself; such would be consonants like K, T, or P. In a voiced consonant however, the voice will be sounded as part of it even before you fully pronounce it, as with consonants G, D, or B (the G as in “get”, in this case). It could be said: voice K/T/P and you get G/D/B; unvoice G/D/B, and you get K/T/P. I expect that this too will probably be a simplification having something to drive MTGuru crazy about.
So of course consonants such as M, N, L, Z, or V are obviously voiced. That a G is voiced, though, isn’t necessarily as easy to see right away until you make as if to pronounce G but hold back for a bit; the voice can still sound in the closed throat before the consonant itself is fully sounded. You could never really do this with K, so we call it “unvoiced”.
Like Peter, I’m struggling with the concept of saying moth, or moths, with anything other than an unvoiced “th”. I don’t think I’ve ever heard it any other way. But then, maybe I haven’t heard an American say “moths”.
Mouse, mice. Moth, mith. (But you need to say it three times fast).
Moth - unvoiced, always.
Moths, moth’s - I’m not sure; it may depend on how much emphasis falls on the word in context.
For example, …
“Look at all those moths.” - probably voiced
“A spider in moth’s clothing.” - probably unvoiced
Let me emphasise (needlessly, I hope) that I have no interest whatsoever in such arguments; I haven’t even hinted that there is a right or a wrong in it, nor would I seek to.
I have noted that in practise there are two modes of pronouncing the plural as opposed to the singular, and it is evident to me that this is usually learned at the hearth. But if anyone should suggest that one or the other indicates education or the lack of it, that is a proposition worthy only of being mocked. It may, however, be a very regional thing, for no one in memory - in my region, for I’m not that well-travelled - has ever taken issue with me on it. I do find that possibility interesting, but must leave it to better heads to propose the why of it.
I have only asked for the show of hands in a spirit of research (for as idle and inconsequential as it might be); that is all. Far be it from any of us to stoop to being prescriptivists in this most flexible of instances. 
Heheh. I like that. 
Misunderstanding alert, Jason! So please take another look at what I actually wrote (‘wondering why I’d need to speak possessively of them or change my pronunciation if I did’), taking the ‘need’ (and remember I was somewhat daftly trying to visualise why I might need to talk about ‘my moths’!) at a purely personal level.