Miami rapper Rick Ross scores his second straight chart topper on The Billboard 200 as Trilla (Slip-N-Slide/Def Jam) debuts at No. 1. The set sold 198,000 units in the United States, according to Nielsen SoundScan, an improvement over the 187,000 copies shifted by 2006's No. 1, Port of Miami.

The multilabel NOW 27 compilation is new at No. 2 with 169,000, the lowest opening week for a regular NOW album since the first edition bowed in 1998 with 48,000. Of the 27 installments of the regular NOW line, all but four have debuted with more than 200,000.

Snoop Dogg's Ego Trippin' (Geffen) debuts at No. 3 with 137,000, fueled by the top 10 Hot 100 success of the single "Sensual Seduction." However, this is the lowest first-week sales total for any of the veteran rapper's studio albums.

Jack Johnson's Sleep Through the Static (Brushfire/Universal) slips 2-4 with 55,000 (-14.6 percent), while Alan Jackson's Good Time (Arista Nashville), which topped the chart last week, plummets 55.4 percent to No. 5 with 53,000.

New at No. 6 is rapper Fat Joe's The Elephant in the Room (Imperial), which sold 46,000 copies. Sara Bareilles' Little Voice (Epic) holds at No. 7 in its 24th chart week, with sales of just over 40,000 units, a 2.3 percent uptick. Janet Jackson's Discipline slips 3-8 in its third frame on a 34.5 percent decline to 38,000.

Erykah Badu's New Amerykah: Part One (4th World War) (Universal Motown) is down 6-9 to 35,000 (-16 percent), while Miley Cyrus' The Best of Both Worlds Concert (Walt Disney) arrives at No. 10 on sales of 34,000.

Just below at No. 11, the NOW That's What I Call 80's compilation lands with about 400 copies short of the Cyrus album. NOW 80's was also available in an 80-track edition exclusive to Apple's iTunes Store. The latter is charting separately and its sales are not counted in the 20-track version's tally.

The only other debut in the top 50 comes from American Idol judge Randy Jackson's Randy Jackson's Music Club: Vol. 1 at No. 50. The set, released on his own Dream Merchant 21 imprint through Concord, sold 13,000 copies. Its first single, "Dance Like There's No Tomorrow," features fellow Idol judge Paula Abdul.

The Columbia soundtrack to the film August Rush reenters the chart at No. 55 with 12,000 copies sold this week. The movie's "Raise It Up" was recently nominated for a best original song Oscar. Metal outfit Meshuggah arrives on the chart at No. 59 with Obzen (Nuclear Blast), which sold 11,000 copies.

Album sales this week are up 3.4 percent over the prior week to 7.94 million, but down 6.6 percent over the same week in 2007.