Harold, il mio amico: I think that's really an interesting point. To be honest that distinction never would have occurred to me. In American English 'shall' seems to be fading into disuse. Used facetiously at times to be sure as in "Oh, shall we darling?" So thanks for pointing that out. Your comments are never "shall-ow" my friend.
christine: I agree completely that it should be accepted; to be honest, as an AE speaker, I wasn't aware of that "obligatory" usage until starting on DL and seeing what speakers of mostly BE had to say. That said, there are few native speakers in the US that use 'shall' -- maybe we're too 'shall-low', I don't know, but as I & others have said, using it here in the states would strike the ears of listeners as snobbish or pretentious.
RichardWil: See my comment above. What's correct or not is for those who use the language on a daily basis to determine and as I noted, use of "shall" in the US will make you come across as a snob, regardless of whether or not it's grammatically correct & whether or not it's what the norm happens to be elsewhere.
RichardWil: I agree with you completely. I was earlier responding to your comment that using "will" is incorrect. For me, both are correct, perhaps "shall" more grammatically so than "will" but depending upon where one's speaking, I'd say one is simply more acceptable, more common than the other.
pedrevans: I agree w/ you as other have also pointed out. That said, use of 'shall' in American English has all but been phased out, which isn't good or bad, it's simply what it is. On the other hand, I can envision its use here as a contrast to "will". For me the two sentences: "Where will we go tomorrow" and "Where shall we go tomorrow" have different connotations. The first for me is simply a neutral future question. The second implies to me that we've already done a number of things, gone to a number of places, perhaps this week, yesterday, today and the person is now asking, 'So, what's next? Where shall we go tomorrow?" In other words 'shall' is used in AE with particular emphasis and not simply as a future auxiliary. Thinking about it further, I'd say that in AE 'shall' is also used for emphasis, e.g. MacArthur's famous statement of resolve: "I shall return" -- which is far more forceful and resolute than had he simply exclaimed: "I will return" or worse "I'll return".