Tina Turner's version of "Proud Mary" has sold the most copies. Her rendition was released in 1971 on the album "Workin' Together" by Ike & Tina Turner and became a major hit.
The Lightning Thief has sold the most copies at more than 1.2 million copies.
Green Eggs and Ham is the Dr. Seuss book that has sold the most copies, with over 8 million copies sold worldwide.
The Eagles, Greatest Hits: 39 million sold copies
the Bible
Thriller.
Good Girl Gone Bad, with 2 million copies sold in the US.
150 million copies of LOTR have been sold. It is also the second most sold novel in the world. My source: Wikipedia
The highest-selling version of The Sims that has sold the most copies as of 12/23/2012, is The Sims 3. Since the game was released in 2009, more than ten million copies have been sold.
the Beatles
The Bible
Slim shady
Call of Duty Black Ops has just broken the record for most copies sold and not just for the series