Flo Rida's "Low" remains a juggernaut atop the Billboard Hot 100, as it enters a fourth week at No. 1. The songs in the next four positions are all unchanged over last week, with Alicia Keys' "No One" at No. 2, Timbaland's "Apologize" featuring OneRepublic at No. 3, Chris Brown's "Kiss Kiss" featuring T-Pain at No. 4 and Fergie's "Clumsy" at No. 5.

Brown scores another new top 10 hit at No. 6 with "With You," which jumps from No. 12. On Hot Digital Songs, "With You" is one of only 10 songs to post actual sales gains, as the digital market continues to come off its post-holiday peak.

Finger Eleven's "Paralyzer" remains No. 7 on the Hot 100, Colbie Caillat's "Bubbly" drops 6-8 and Jordin Sparks' "Tattoo" slips 8-9. Sean Kingston's "Take You There" rounds out the top 10 with a 13-10 increase and is the chart's top digital gainer.

Rotund rapper Fat Joe has the Hot 100's top debut at No. 81 with "I Won't Tell" featuring J. Holiday. The track will appear on Fat Joe's next Imperial album, "Elephant in the Room," due March 11.

With a sixth week at No. 1 on Hot Country Songs, Taylor Swift's "Our Song" becomes the longest-running chart-topper there since Carrie Underwood's "Jesus Take the Wheel" reigned for the same period in January 2006. Swift also has the top debut on Hot Country Songs with "Pictures To Burn" at No. 52.

Alicia Keys' "Like You'll Never See Me Again" is No. 1 on Hot R&B/Hip-Hop Songs for a fourth week. Missy Elliott has the top debut at No. 57 with "Ching a Ling," which will appear on the upcoming "Step Up 2 the Streets" soundtrack and on her next album, due in May.

Seether retains its stranglehold on Billboard's rock charts with "Fake It." It's No. 1 on Modern Rock for a fourth week and leading Mainstream Rock for an eleventh.