The Bible translations that call themselves the literal translations have a funny way of defining 'literal'. What they really mean is that the number of words in a sentence in the original is as close as possible to the number of words in the translation. At least that's what's going on in I Corinthians 3:16-17. There is a difference in translation philosophy between preserving the form of the original and preserving the sense of the original. Those are different elements, and erring on either side means preserving a different element of the meaning of the original.
That's not what's going on in the differences between the translations that say they're more literal amd the ones that say they're more dynamic in I Corinthians 3:16-17. The main difference with this passage is not about preserving the form vs. preserving the sense. It's about preserving one aspect of the form (and therefore one element of the meaning) vs. preserving a different aspect of the form (and therefore a different element of the meaning). First consider the following translations of the two verses in question:
NASB: Do you not know that you are a temple of God and that the Spirit of God dwells in you? If any man destroys the temple of God, God will destroy him, for the temple of God is holy, and that is what you are.
ESV: Do you not know that you are God's temple and that God's Spirit dwells in you? If anyone destroys God's temple, God will destroy him. For God's temple is holy, and you are that temple.
HCSB: Don't you know that you are God's sanctuary and that the Spirit of God lives in you? If anyone ruins God's sanctuary, God will ruin him; for God's sanctuary is holy, and that is what you are.
NIV: Don't you know that you yourselves are God's temple and that God's Spirit lives in you? If anyone destroys God's temple, God will destroy him; for God's temple is sacred, and you are that temple.
TNIV: Don't you know that you yourselves are God's temple and that God's Spirit dwells in your midst? If anyone destroys God's temple, God will destroy that person; for God's temple is sacred, and you together are that temple.
NLT: Don't you realize that all of you together are the temple of God and that the Spirit of God lives in you? God will bring ruin upon anyone who ruins this temple. For God's temple is holy, and you Christians are that temple.
There are at least a few places where some of these translations differ, but what I'm interested in is how they handle the second person pronouns. Notice that the NASB, ESV, and HCSB translate it as simply 'you'. The NIV and TNIV translate the first one as 'you yourselves', but the NIV joins the NASB, ESV, and HCSB with the second and third instances. The TNIV translates the second as simply 'your' but the third as 'you together'. The NLT translates the first as 'you together', the second as 'your', and the third as 'you Christians'.
Why are these results so different? The problem facing the translator is that these are all plural pronouns. If you translate it the way the so-called literal translations insist on doing, you end up making it sound as if Paul is saying each person is the temple of God. That's not at all what he's saying. This is a response to the divisions in the Corintian church, and he's telling them that they as a church need to start acting like the temple of God that they collectively are. He elsewhere does call the individual Christian's body the temple of te Holy Spirit, but that's not what he's saying here. Those so-called literal translations lose the literal meaning of this text by insisting on translating in a way that makes the second person pronouns appear singular.
The other translations, the ones often called more dynamic, are therefore insisting on translating the form of the original, or at least on translating one crucial aspect of it -- the plural form. The so-called literal ones preserve the form in trying to keep as closely as possible to the original word count. Apparently it's much worse to have more words in the translation than it is to translate plural pronouns as plural. They're thus ignoring a crucial element of the form by focusing on a relatively unimportant aspect of the form. That sounds completely silly to me. I do want to note that the ESV isn't as bad in this as the other two, because it has a footnote saying that 'you' is plural in those two verses. Many readers don't read footnotes, though (shame on them!), and it's best to have any crucial aspects of the meaning that are absolutely clear, as is the case here, in the text itself if it can be done without compromising something more important.
Can it be done in this case without sacrificing something more important? The NLT adds the word 'Christians' to the third occurrence. Given that it's designed to be a translation for people who don't know English very well or who are in their younger years, this isn't as bad as if a translation for adult speakers of English as a first language did something like this. Still, there are better ways, as the other translations show. The TNIV seems to me to be the only one among these translations that accurately renders the third occurrence: "you together are that temple". The so-called literalists will insist that the word 'together' is not in the original. Well, that's correct, but neither is the word 'you', which is an English word. What is there is some Greek word, and the issue is how best to render that word given that it's plural. Translating it as 'you' doesn't cut it. The ESV, NASB, HCSB, and NIV all do a worse job translating that word than the TNIV does.
What about the other instances? All of them but the TNIV fail to capture the plural at all. Does the TNIV do any better? I don't like how they did it. The sense is that the Spirit of God dwells in them as a group. That's why it says "in your midst". Well, that's better than all the others, but I think it's misleading in another way. It sounds as if the Holy Spirit is sort of weaving in and out among them all. That's not what Paul says. He says the Holy Spirit is in them, not among them. I don't know a better way to translate this, so I'm not going to judge any of these translators harshly. I just want to make it clear how hard it is to capture the meaning of the original sometimes, and complaining that someone isn't literal (whatever you might mean by that) sometimes misses the point.
The first instance is the clearest, and any failure later on might be excused because how they translate this one might affect interpretation of the later ones. There are really two occurrences here (and four total), but I've been treating these as a unit. The NASB, ESV, and HCSB fail to capture the literal meaning by translating it with the solo 'you'. The NIV and TNIV use 'you yourselves', while the NLT uses 'all of you together'.
Again, the so-called literalists will complain that 'yourselves' and 'all of ... together' are not in the text. Again, they are correct, but neither is 'you'. In fact, this time it's even worse than just having one Greek pronoun. There's no pronoun. All there is this time is the second-person plural form of the verb 'to be'. There's one Greek word there for the subject and the plural, and the real question is how it is most accurately translated. We need at least two words for that one Greek word, but the so-called literal translations seem to want to likit it to no more than that. Why?
Using the reflexive pronoun 'yourselves' might suggest some reflexive meaning in some contexts, and maybe they want to limit that effect, but I can't see such an effect here. It's not as if you are doing something to yourselves. It's that you yourselves (plural) are the temple (singular).
The other element this word might convey is emphasis on the group referring to. Sometimes Greek and Latin emphasize a second-person subject that's already understood by adding a pronoun, which doubles the reference. The 'you' in English is understood in the verb, and adding the pronoun in the Greek adds emphasis. Translating this as "you yourselves" conveys that it isn't just the normal way of saying that you did something, which is to have a second-person ending on the verb. It's got a pronoun too, and "you yourtselves" conveys the extra emphasis. Well, I suppose that's a danger of translating it this way. Which is worse, erring on the side of reflecting a possible emphasis on the subject that isn't there or erring on the side of not reflecting that fact that the verb is plural? I say the latter is much worse.
The only other element I can think of that adding this word adds in terms of meaning is that it's plural. That's exactly what we want to add. Therefore, this seems like exactly the right way we want to translate a plural second-person pronoun in a context like this. Kudos to the NIV and TNIV for getting it right. I can't think of any worrisome way that the NLT translation adds further meaning with 'all' or 'together', but perhaps parsimony can be good if there's no need for the extra words. For that reason I don't really mind what the NLT did, but the NIV and TNIV did a little better at achieving the same purpose.
My conclusion is that the TNIV does the best job with these verses, at least with respect to these pronouns. There are other places of difference here that I'm not talking about at all. On this decision, the TNIV is actually the most accurate of all these translations, and it achieves this by paying more attention than the others to the form of the original. Yet in doing so, it somehow violates whatever intuition lies behind the popular conception of translating literally. I say that's just a good argument against using the popular conception of translating literally and sticking with more precise goals of preserving the meaning that the form conveys while also trying to preserve as much as you can of the sense of the original without losing equally important aspects of the meaning that come with the form, all the while sounding like English.
A translation that really did that would, I say, be more literal than the NASB, because it often fails to do that. In this case, with respect to the issue I've been focusing on, the TNIV accomplishes that best. The so-called literal translations simply cares too often and too much about how many words are in the original and how many words are in the translation, and it's far less accurate to the literal meaning to focus on that more than whether a word is singular or plural. Therefore, what the TNIV does is to translate the literal meaning of the word in question in a way these other translations don't.
Addendum: the KJV had access to 'ye', which is no longer a word in standard English, never mind in most people's English. That truly is a second-person plural. If we had that, we wouldn't run into these problems. That doesn't mean the KJV is a better translation with respect to this issue. It was better for the time, but it's not better now, because hardly anyone even knows that 'ye' was a second-person plural.
Also, the NKJV has the same exact rendering of the pronouns as the NASB, ESV, and HCSB. I picked the translations I use the most. I could have chosen others. My point is about translation theory, not about particular translations. It just has the deliciously ironic result that the TNIV is the most accurate of the ones I looked at. I still prefer the ESV overall to any other translation at the moment. On this issue, though, the ESV fails to render the meaning of the verse as accurately as it might have.