Here's the list that helped inspire me to pick up a few very interesting-seeming non-fiction books to read this year...
Time's Top 100 Non-Fiction books published since 1923:
http://www.goodreads.com/list/show/12719.Time_Magazine_s_All_TIME_100_Best_Non_Fiction_Books
Here's the Time's list of the top 100 Novels, they released this in 2005:
http://entertainment.time.com/2005/10/16/all-time-100-novels/#all
The Guardian has a couple of similar lists, less US-centric than Time Magazine perhaps.
The 100 greatest non-fiction books (updated June 2011)
The 100 greatest novels of all time (originally from 2003 but I think has been updated since)
Apparently these are still in the top 5 most visited pages on the The Guardian's books site.
And there's this: The top 100 books of all time (from 2002). 100 authors from 54 countries around the world were asked to nominate the ten books which they felt have had the most decisive impact on the cultural history of the world, and left a mark on the authors' own thinking.