I agree with your argument immediately above Mat, that it should not have been hijacked by the JW's.
And I think you touch on a good reason why most Christian denominations do not use it, they are not that used to it, most translations almost leave it out completely, but there is a reluctance to get the christian God too firmly linked to the God of the early Old Testament.
As to saying the word, if you were appearing on a serious T.V show with emminent Bible Scholars, I think you would hesitiate to sound as ignorant as the average JW,by simply using that name for God, and would say something like, " Jehovah, the Yaweh of the Israelites..... "
Thanks for pointing out what a proper name is, but my point was that YHWH has always been more than that, even in that early usage in Exodus, it was not for the Israelites benefit so that they could use it in a liturgical way, as a word to address God by.
As it was connected etymologically to what God "is" in a number of ways, much of his Eternal Godship being contained in the Name, the Israelites would naturally think of its meaning, and hence it was natural that they grew to view it as ineffable.