The 1966 Hugo awards make this one of the Top 5 all-time series.
Here's the full list (http://www.locusmag.com/SFAwards/Db/Hugo1966.html
# "Foundation" series, Isaac Asimov
# "Barsoom" series, Edgar Rice Burroughs
# "Future History" series, Robert A. Heinlein
# "Lensman" series, Edward E. Smith
# The Lord of the Rings, J. R. R. Tolkien