Best Selling Albums of All Time

29 Million

• Eagles: Their Greatest Hits, 1971–1975, Eagles (Asylum)

27 Million

• Thriller, Michael Jackson (Epic)

23 Million

• Led Zeppelin IV, Led Zeppelin (Atlantic)
• The Wall, Pink Floyd (Columbia)

22 Million

• Back in Black, AC/DC (Epic)

21 Million

• Greatest Hits, Volumes I & II, Billy Joel (Columbia)
• Double Live, Garth Brooks (Capitol Nashville)

20 Million

• Come On Over, Shania Twain (Mercury Nashville)

The rest of the best are here.