Though, whence comes the idea that English is sister and daughter to English? I do not think it is either. In a fashion it is a cousin, but the splitting point lies so far back (some five thousand years), that it is nearer a distanct cousin. At any rate, English is Germanic, which in essence is quite different than Latin, though it does share some cognates. One might, however, argue that Greek and Sanskrit are closer than are English and Latin.
There are, as you say, some loan-words, but these are actually rarer than most people think. Certainly not enough for it to be classified as a descendant. I think the total runs maybe to 2% of our vocabulary, if that. To be able to discern these words is hardly a good reason to learn Latin, as the majority of words we employ have become so common as to not need explaining (ie. the word 'majority' for one.) Those of a rarer form are generally used by those attempting to pepper their language with complex words, and as such their use is marginal at best.
Nonetheless, I must disagree strongly with your statement about translations not doing the original justice. Having read, for example, Homer in the original, and on the other hand Richmond Lattimore's translation, I will say that it comes extremely near. Certainly there are things that are difficult to convey, but such problems exist even to those attempting to read the orignal (for example, what does 'bathukolpos' applied to the Trojan women mean? The 'deep-girdled' that Lattimore gives it as? Or 'with deep cleavage'? The word merely means 'deep hollow', and much of the context is difficult to ascertain even in Greek. The same goes for a word such as amunon.) The point is, unlike some would claim, reading the original is not always that much better than a translation, and there are many translations that can beautifully convey not only the words of the original, but also the mood and feeling. I will always maintain that translations can do justice to the original, and I'm saying this from many years of experience in the matter. Definitely there are artistic nuances that don't quite translate... but again, even in the original those are sometimes obscure.
Of course, those of us who do study the languages do have some innate love for the original. I would not study it if I did not. But it is an eccentric love that is unneccesary for the vast majority. The most of people can get a very good sense of the originals via translation. To read the original work remains with those who have a peculiar linguistic madness for the subject.
Nevertheless, I will still maintain the value of these languages in a pedagogical aspect against both you and Shee. It remains extremely relevant not because of mere etymology (as, Thought, you have mainained), but because of larger shared linguistic heritage. Unlike languages like German there still exists the strong use of declension and conjugation - certainly more prevalent in German than in English, but even there it's mostly faded. This structure in turn helps with the proper use of English simply because the inherent conception of how language works remains very much the same. You will rarely see me misuse a reflexive, and so on and so forth, in part because in Latin such uses are so basically structural that it continually highlights proper use in English.
Of course, I will admit there are several errors that arise from such Latin scholarship. For example, the idea that we cannot begin sentences with certain words comes from a post-postitive use in Latin and Greek that does not exist in Latin. Likewise split infinitives, actually quite useful in English, somehow became taboo to the grammarians on account of Latin. Grammatically speaking, there is nothing wrong in English with saying 'to boldly go'. It very nicely ties the adverb more strongly to the verb in a way that 'to go boldly' or 'boldly to go' does not. There are such nuances in Latin as well, but they do not work in English becaues of the way our language is structured.
All the same, the concepts of case, tense, mood, of person and so forth, remain very much the same, and their proper use is best taught by a language in which they still remain prevalent. As such, in part because of its fossilised nature, it serves as an excellent tool to teach these things. Of course, I do not think that it is prudent for most to learn Latin to the extent that they can write in it, or read more than the most basic texts. But a basic understanding is invaluable to the understanding of language as a whole, and I think structures future learning and thought in a very beneficial way that even learning other modern languages cannot quite match. And, I will say, one reason for this is that the learning of most modern languages is from the view of conversation, rather than grammar. As such, you learn the 'how', and not the 'why', and it is this why that is helpful in later learning, even outside the realm of languages. Not to mention, there is nothing that teaches patience so much as sitting and writing down the pages of paradigms for Latin or Greek. Certainly that is a trait that will stand any future students, indeed all of the population, in good stead.
So it must be maintained that though fossilised, Latin is only dead if we wish it to be. The very fact that I choose to write poetry in Latin underscores this. To me, it remains very much alive.
And Thought, thank you very much for your well-written Latin statement, but ironically, in the most recent poem I was writing, I was saying just the reverse. It is mostly incomplete, but the first words were running something along the lines of 'quisquis gentium et aetatem posteriore' ('whoever of races and times yet to come'... not yet structured in the metre, and I'm still uncertain if this 'of' demands genetive or ablative... ablative is used to dentote a place of origin, but genetive can be used in a partative sense, and I can't figure out which is to be used in this case. I've gone from one to the other, here retaining the genetive, but also going back to the ablative now and again) and continues on to a conclusion of 'quis ... rumor inanis ero' (for whom I will be an untrustworthy rumour'), and at last will conclude with 'scripta sodali sunt ingenii...' (these writings are for my friend of genius...) the dedication to whom I have written the poem as being, for those reading it, the name to be remembered above mine. Though my body and name be in the dust, let hers remain exalted. Or something along those lines. I'm still needing to work on it.
I suppose writing in English might be more accessible. But there are those amongst my friends with far greater Latin ability than me (though I am the only one that attempts such writing), and as such it is not so obscure to the intended audience.
Post Scriptum
Note that I have said 'greater Latin ability than me.' My mother, who knows English and German, has often critiqued this use, saying it should properly be 'than I.' However, because of my knowledge of language via Latin, I have successfully maintained the use of 'me'. The difference is that with the use of 'I' the 'than' begins a clause, in the anticipation of another verb 'ie. greater ability than I possess.' However, the use of 'me' is perfectly correct if the 'than' is being used prepositionally, in which case the 'than' takes an accusative, hence, 'me'. However, without the linguistic grounding of Latin such things are difficult to spot, and are often mistakenly criticised. I, of course, have used this power for evil at times, arguing via absurd linguistic reasoning that something I said most assuredly in error was, by some obscure grammatical use, correct.
Post Post Scriptum
Maybe this thread needs a split...