Ahem, it was I who posted that thread, tgwbs....
I agree that it's interesting that Tolkien is included in a 'must-read', usually he only makes the 'most popular' polls....
One thing that strikes me about both this list and the one I mentioned is the absence of foreign classics.
A "read before you die" list that doesn't include Tolstoy is fundamentally flawed IMO. No Zola, Balzac, or Flaubert either, TUT.
Tolkien meanwhile would I suspect have been tutting about the absence of classical literature.
I have read over half of the books on that list, and most of those near the top (...I too am very fond of To Kill a Mockingbird....) better get cracking I suppose on the rest, never know how much time one's got...