While it probably would have become a single eventually, "Breathe" was not Faith Hill's first choice as the cut to introduce her fourth album. Intending to debut the song on the upcoming Country Music Assn. Awards telecast in 1999, Hill had been leaning toward something uptempo. Husband Tim McGraw and her label, Warner Bros. Nashville, convinced her otherwise and "Breathe" went on to become a six-week No. 1 on Hot Country Songs in 1999 and a 17-week chart-topper on Adult Contemporary early the next year before reaching No. 2 on the Hot 100 in April 2000 and lingering on the chart for more than a year. --Ken Tucker

Lifehouse made quite a splash with debut single "Hanging By a Moment." The track peaked one spot shy of No. 1 on the Hot 100, but that didn't keep it from becoming 2001's top song, making Lifehouse the first male rock group to rule the annual recap since Chicago did in 1989 with "Look Away." "Moment" launched at rock radio and migrated to top 40, topping the Modern Rock, Adult Top 40, Top 40 Tracks and Hot 100 Airplay charts along the way. Such cross-format success was the main reason the Los Angeles band was also named the year's top new pop act. --Christa Titus

Calling "How You Remind Me" a "breakthrough song" for Nickelback is an understatement akin to saying Michael Phelps is a good swimmer. The accolades that the Canadian rock band's first top 40 hit-and eventual No. 1-amassed include the band's first Grammy nomination, a Juno Award and multiple No. 1 rankings on Billboard's 2002 year-end charts. The ubiquitous single, which ultimately spent 49 weeks on the Hot 100, also helped propel parent album "Silver Side Up" to six-times-platinum. --Christa Titus

While he had visited the top 40 of other Billboard charts as early as 1999's "Your Life Is on the Line" (No. 37 on Hot Rap Songs), 50 Cent's first Hot 100 No. 1 was 2003's "In Da Club." After its No. 67 debut on Jan. 11, 2003, "Club" rose to No. 1 March 8 and reigned on the Hot 100 for nine weeks. The track, which remained on the tally until August, was spun everywhere from teen birthday parties to Oprah Winfrey's own birthday bash. 50 Cent's next single, "21 Questions," followed "In Da Club" to the top spot just a month after "Club" vacated it and remained there for four weeks. In fact, during one chart week in May 2003, "Club" was one of four Hot 100 titles that featured the rapper, including "21 Questions," "P.I.M.P." and Lil' Kim's "Magic Stick." --Hillary Crosley

"Yeah!" was the first single from Usher's fourth studio album, 2004's "Confessions," the follow-up to his multiplatinum third set, 2001's "8701." The crunk and R&B "Yeah!," produced by Lil Jon and Sean Garrett and featuring Ludacris, spent 12 weeks at No. 1 on the Hot 100 and also went to No. 1 on Hot R&B/Hip-Hop Songs and Hot R&B/Hip-Hop Airplay. "Yeah!" helped propel "Confessions" to record-breaking first-week sales. The 1.1 million units the album scanned broke R. Kelly's record of 540,000 copies of 2000's "TP-2.com" for the highest first-week numbers scanned by a male R&B artist in Nielsen SoundScan history. --Mariel Concepcion

After 15 No. 1 songs, Mariah Carey signed an $80 million contract with Virgin and then proceeded to infamously lose her cool during a bizarre 2001 taping of MTV's "TRL" and star in flop film "Glitter." The handful of years that followed didn't produce any substantial solo hits for the singer, who had turned almost everything she touched into platinum. But Carey managed to regroup after her early-'00s rough patch. In 2005, the songstress released comeback album "The Emancipation of Mimi" via her new label, Island Records. The Jermaine Dupri-produced "We Belong Together" was a monster single that sat at No. 1 on the Hot 100 for 14 weeks and helped "Mimi" go on to sell 5.9 million copies, according to Nielsen SoundScan. Since "Together," Carey has returned to No. 1 two additional times for a total of 18 No. 1 Hot 100 singles. Her sum is second only to the Beatles' 20 No. 1 hits. --Hillary Crosley

Written by Canadian singer Daniel Powter, "Bad Day" topped charts throughout the world in 2006, notching five weeks atop the Hot 100 in the spring and ultimately spending 32 weeks on the tally. Powter was the first Canadian artist to top the chart in the four years since Nickelback reigned with "How You Remind Me." After a stint in a popular French Coke commercial that launched it to No. 3 in that country in 2005, "Bad Day" catapulted into ubiquity in the United States when it was used as the farewell music for eliminated contestants during the fifth season of "American Idol" in early 2006. The midtempo Chicken Soup for the Mildly Bummed soft rocker would also eventually reach No. 1 in the United States on four additional Billboard charts: Adult Contemporary, Adult Top 40, Pop 100 and Hot Digital Songs. --Jeff Kolhede

Of Beyoncé’s eight No. 1s (four solo, four with Destiny’s Child), "Irreplaceable" became her longest-reigning solo hit, topping the Hot 100 for 10 weeks. But Beyoncé also earned a bilingual hit with the track. The Spanish version of "Irreplaceable" reached No. 4 on Billboard's Hot Latin Songs chart for the non-Spanish-speaking singer. "I have it all written out in phonetics," producer Rudy Perez told Billboard while he was doing the Spanish studio work with Beyoncé. "We read the lyrics together, and I tell her exactly what she's saying. Even if you don't explain it, she'll ask you because she's very meticulous." --Ayala Ben-Yehuda