20. Justin Bieber - Beauty And A Beat
at The Staples Center on October 2, 2012 in Los Angeles, California.
19. Olly Murs - Troublemaker
LONDON, ENGLAND - JANUARY 16: Singer Olly Murs speaks on stage during the official launch to mark the FA's 150th Anniversary Year at the Grand Connaught Rooms on January 16, 2013 in London, England. (Photo by Ian Walton/Getty Images)
18. Swedish House Mafia - Don't You Worry Child
NEW YORK, NY - DECEMBER 16: (FOR EDITORIAL USE ONLY) DJ's Axwell, Steve Angello and Sebastian Ingrosso of Swedish House Mafia perform at Madison Square Garden on December 16, 2011 in New York City. (Photo by Michael Loccisano/Getty Images)
17. Maroon 5 - Daylight
XXX performs during the 2012 F1 Singapore on September 22, 2012 in Singapore.
16. Justin Bieber & Will.I.Am - #thatpower
NEW YORK, NY - FEBRUARY 05: Justin Bieber visits "Late Night With Jimmy Fallon" at Rockefeller Center on February 5, 2013 in New York City. (Photo by Theo Wargo/Getty Images)
15. Icona Pop - I Love It
NEW YORK, NY - SEPTEMBER 06: Singers Caroline Hjelt (L) and Aino Jawo of the musical group Icona Pop attend the Nicholas K Spring 2013 fashion show during Mercedes-Benz Fashion Week at The Studio at Lincoln Center on September 6, 2012 in New York City. (Photo by Stephen Lovekin/Getty Images for Mercedes-Benz Fashion Week)
14. Taylor Swift - 22
LONDON, ENGLAND - FEBRUARY 20: Taylor Swift performs on stage during the Brit Awards 2013 at the 02 Arena on February 20, 2013 in London, England. (Photo by Matt Kent/Getty Images)
13. The Lumineers - Ho Hey
NASHVILLE, TN - DECEMBER 05: Wesley Schultz, Neyla Pekarek, and Jeremiah Fraites of The Lumineers speak onstage at The GRAMMY Nominations Concert Live!! held at Bridgestone Arena on December 5, 2012 in Nashville, Tennessee. (Photo by Kevin Winter/Getty Images)
12. Alex Clare - Too Close
LONDON, ENGLAND - FEBRUARY 20: Alex Clare attends the Brit Awards 2013 at the 02 Arena on February 20, 2013 in London, England. (Photo by Eamonn McCormack/Getty Images)
11. Britney Spears & Will.I.Am - Scream & Shout
at a taping of We Will Always Love You: A GRAMMY Salute To Whitney Houston on October 11, 2012 at the Nokia Theatre L.A. LIVE in Los Angeles, California. The show airs November 16, 2012.
10. P!nk - Just Give Me A Reason
attends the St. John's Health Center's Power Of Pink benefiting The Margie Petersen Breast Center at Sony Studios on November 12, 2012 in Los Angeles, California.
9. Demi Lovato - Heart Attack
LOS ANGELES, CA - FEBRUARY 14: Recording artist Demi Lovato attends the Topshop Topman LA Grand Opening at The Grove on February 14, 2013 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images)
8. Rihanna - Pour It Up
LOS ANGELES, CA - FEBRUARY 10: Singer Rihanna arrives at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Jason Merritt/Getty Images)
7. Pitbull - Feel This Moment
<> on August 9, 2012 in Los Angeles, California.
6. Krewella - Alive
Festival goers enjoy a set by a dubstep DJ at the "Lounge on the Farm" festival near Canterbury in Kent, on July 8, 2011. Five years ago, dubstep was just another fresh but obscure strain of dance music, limited almost exclusively to a handful of nightclubs in south London. Today it is taking over dancefloors worldwide. Born out of drum'n'bass and the 2-step UK garage movement which propelled Craig David to fame, dubstep completed its journey from quirky curiosity to commercial success story earlier this month (eds: earlier in July) when DJ Fresh's "Louder" hit the top of the UK singles chart. AFP PHOTO/Leon Neal TO GO WITH AFP STORY BY JAMES PHEBY *BRITAIN-ENT-MUSIC-DUBSTEP* (Photo credit should read LEON NEAL/AFP/Getty Images)
5. Bruno Mars - When I Was Your Man
performs onstage at the 54th Annual GRAMMY Awards held at Staples Center on February 12, 2012 in Los Angeles, California.
4. Rihanna - Stay
Singer Rihanna performs live on stage as part of her 777 tour at The Forum on November 19, 2012 in London, England.
3. Calvin Harris - Sweet Nothing
LOS ANGELES, CA - SEPTEMBER 06: DJ Calvin Harris poses in the press room during the 2012 MTV Video Music Awards at Staples Center on September 6, 2012 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images)
2. Macklemore - Thrift Shop
SEATTLE - APRIL 08: Seattle recording artist Macklemore performs a tribute to Mariners broadcaster Dave Niehaus, who passed away last November, prior to the Mariners' home opener against the Cleveland Indians at Safeco Field on April 8, 2011 in Seattle, Washington. (Photo by Otto Greule Jr/Getty Images)
1. Justin Timberlake - Suit & Tie
AUSTIN, TX - MARCH 16: Justin Timberlake performs at Myspace Secret Show @ SXSW on March 16, 2013 in Austin, Texas. (Photo by Jason Kempin/Getty Images for Myspace)