There is of course the opposite dream: having only the 3 or 4 best books that you re-read, carry around, etc. Nothing is quite like the moment when some smart editor/publisher gives you your dream. The Library of America books, if they had some better notes, would be sort of like that. But some huge books over the years in the "3 or 4 books" category:

The complete Aristotle, 2 vols. (Way to go, Jonathan Barnes).
The complete Plato (thank you Bollingen)
The beautiful hard cover edition of Montaigne's essays (Donald Frame trans.)
Singleton's Dante.
The Norton Shakespeare (finally, after 20 years of waiting)
The Norton Anthology (Third Edition, 2 vols, is probably the best)
The New Oxford Book of English Verse (Helen Gardner's, the new one is a pop mess)
The Longman's Milton (A truly wonderful piece of scholarly work)

What do we lack? We lack a good edition of the King James Bible with notes, updated editorial references, etc. Will somebody out there do it, please!!!

With these in hand, you could do very well for yourself for many years, and be more educated than 99% of those who graduate university these days.

yours,

Peter T.