As expected, Britney Spears' "Circus" makes a big bow at the top of The Billboard 200, becoming her fifth No. 1. The Jive set moved 505,000 copies in the United States, making Spears the only act in Nielsen SoundScan history to have four albums debut with 500,000 or more.

Since SoundScan began tracking data in 1991, only four acts -- aside from Spears -- have notched three 500,000-starts: 2Pac, 50 Cent, Garth Brooks and Jay-Z.

Previously, her second, third and fourth sets all racked up half-million weeks: 2000's "Oops! I Did It Again" started with 1.3 million, 2001's "Britney" debuted with 746,000 and 2003's "In the Zone" entered the chart with 609,000. Among female artists, only four have earned more No. 1 albums: Barbra Streisand (eight), Madonna (seven) and Mariah Carey and Janet Jackson (both with six).

Taylor Swift's Big Machine album "Fearless" stays put at No. 2 for a second week with 193,000 copies, a 28% sales decline. Beyonce's "I Am ... Sasha Fierce" (Music World/Columbia) ascends 4-3 with a 41% downturn to 153,000. Last week's chart-topper, Kanye West's Roc-A-Fella/Def Jam set "808s & Heartbreak," slips to No. 4 on a 69% dip to 142,000.

Nickelback's "Dark Horse" (Roadrunner) climbs 7-5 with 133,000 (-25%), while the Chop Shop/Atlantic soundtrack to "Twilight" ascends 8-6 with only a few hundred copies short of "Dark Horse," also at 133,000 (-18%).

Akon's Konvict/Upfront/SRC/Universal Records album "Freedom" debuts at No. 7 with 111,000. The singer's last set, 2006's "Konvicted," bowed at No. 2 with 284,000 and spent 68 weeks on the chart. It has sold 2.9 million so far.

The soundtrack to Disney's "High School Musical 3: Senior Year" re-enters the top tier 11-8 on a 7% decrease to 91,000. The multi-label hits compilation "Now 29" keeps the No. 9 spot warm for a second week with 90,000 (-38%), as David Cook's self-titled debut from 19 Recordings/RCA hold at No. 10 for a second week on a 22% decline to 87,000.

Only two other albums bow inside the top 50: Scarface's "Emeritus" (J Prince/Rap-A-Lot 4 Life/Rap-A-Lot Asylum) enters at No. 24 with 42,000, while a Neil Young concert set, "Sugar Mountain -- Live at Canterbury House 1968" (Reprise), debuts at No. 40 with 26,000.