They both have done phenomenal work. Before you complain that these two aren't the best do research. Brief history of Hans Zimmer: Zimmer's career hit a turning point when, based on the strength of his score for the South African film A World Apart, he was asked to write the score for Rain Man (1988). His work on the film earned him an Academy award nomination, and he subsequently found himself scoring an increasing number of high-profile films, including Driving Miss Daisy (1989), Days of Thunder (1990), Backdraft (1991), and Thelma & Louise (1991). In 1994, Zimmer had his greatest critical success to date with his score for The Lion King, which won both Academy and Golden Globe awards. Two years later, he was again nominated for an Oscar for his work on As Good as It Gets, and in 1998, he was twice nominated for the Academy's Best Original Dramatic Score honor for his work on The Thin Red Line and The Prince of Egypt. Zimmer's Academy run continued in 2000 as he was nominated for Best Original Score for his work on Gladiator. History of John Williams: The son of a movie studio musician, John Williams was trained for the family business at U.C.L.A. and Juilliard. Proficient with several instruments, Williams settled down to a thriving career as a jazz pianist. Billing himself as "Johnny Williams" to avoid confusion with British character actor John Williams, the young composer worked closely with Henry Mancini on the Peter Gunn series, then branched out to compose his own scores for several of the 1960s TV adventure programs produced by Irwin Allen. Williams' first film credit was for the 1959 adventure film Daddy-O. A composer, arranger, and musical supervisor throughout the 1960s, Williams received the first of several Oscars for his orchestrations in Valley of the Dolls (1967). Although he went on to work for a number of directors in the 1970s, Williams' name became conjoined with the twin wunderkinds George Lucas and Steven Spielberg. He composed the music for all three of Lucas' Star Wars films, and for just about all of Spielberg's films, from Sugarland Express (1974) to Saving Private Ryan (1998). Williams' main themes for Jaws, E.T., and Raiders of the Lost Ark were particularly famous, inspiring a large number of imitations, many of which were of markedly fifth-rate value. The number of films Williams has scored is truly dizzying, as is the number of awards he has received for his work: Over the course of his career, the composer has been nominated for 36 Academy awards, winning six for his work on Fiddler on the Roof (1971), Jaws (1975), Star Wars (1977), E.T. (1982), Empire of the Sun (1987), and Schindler's List (1993). Nominated by the academy nearly every year throughout the 1990s, the tireless composer continued his longtime collaboration with Spielberg with such efforts as .I. (2001), Minority Report (2002), Catch Me If You Can (2002), The Terminal (2004), War of the Worlds (2005), and Munich (2005). He also kept busy scoring the latest installments in the Star Wars saga and entering into a the Harry Potter franchise with Harry Potter and the Sorcerer's Stone (2001) and its subsequent sequels. In 2006, Williams won his fourth Golden Globe Award for penning the score to Memoirs of a Geisha. He also composed the score for 2006's Superman Returns--a fitting job for Williams, who had written the music to the original Superman in 1978. In 2011 Williams reteamed with longtime collaborator Spielberg not one but twice, providing the scores for both War Horse and The Adventures of Tintin. Though each of Williams' orchestrations were nominated for Best Original Score at the 84th Academy Awards, the Oscar ultimately went to Ludovic Bource for The Artist.