Mariah Carey earns her sixth No. 1 on The Billboard 200 as her "E=MC2" bows on top. The Island Def Jam set moved 463,000 copies in the U.S., according to Nielsen SoundScan, making it the diva's biggest sales week ever. It's also the highest sales week of the year, surpassing the 375,000 start of Jack Johnson's "Sleep Through the Static" in February.

Carey's last album, "The Emancipation of Mimi," also landed at No. 1 in its premiere week, moving 404,000. She is now tied with Madonna and Janet Jackson for the second most No. 1 albums among female artists. Only queen bee Barbra Streisand, with eight, is ahead of the pack. There's a good chance Madonna will add another No. 1 to her tally though, as her "Hard Candy" album drops next Tuesday (April 29).

Leona Lewis' Syco/J effort "Spirit" slips 1-2 with 95,000 units, a 54% sales decrease. Miley Cyrus' "Hannah Montana/Miley Cyrus: The Best of Both Worlds Concert" Hollywood/Disney album vaults from No. 31 to a new peak of No. 3 with 47,000 -- a 162% gain. The set became available to all music sellers last week after having spent its first five weeks of release as a Wal-Mart exclusive.

New country group Lady Antebellum charges in at No. 4 on The Billboard 200 with its self-titled Capitol Nashville debut, shifting 43,000. Sales were fueled by the single "Love Don't Live Here," which sits at its current peak at No. 11 on the Hot Country Songs tally this week.

The multi-label "NOW 27" compilation slips 4-5 with 39,000 (-17%), as George Strait's "Troubadour" (MCA Nashville) falls 2-6 with 38,000 (-35%). The Fox/Razor & Tie soundtrack to "Alvin and the Chipmunks" likewise descends 6-7 with a 20% sales hit to 32,000. Another soundtrack, "Juno" (Rhino), climbs back into the top tier 46-8 in conjunction with the film's DVD release; the album moved 31,000 copies with a 162% sales increase.

With 30,000 and a 35% sales reduction, R.E.M.'s Warner Bros. set "Accelerate" falls 5-9. Taylor Swift's self-titled Big Machine set rounds out the top 10, ascending 13-10 with a 13% sales boost to 29,000.

After Carey, rock troupe Thrice has the next biggest debut this week at No. 17 with "The Alchemy Index, Vol. 3 & 4: Air & Earth" (Vagrant), selling 21,000 units. With only a few hundred fewer, Rush's double-disc Atlantic set "Snakes & Arrows: Live" starts right behind at No. 18, also with 21,000. Other debuts this week include metal outfit Children Of Bodom's "Blooddrunk" (Fontana/Universal, No. 22, 19,000), Nickelodeon duo the Naked Brothers Band's "I Don't Want to Go to School" (No. 23, 19,000) and Tristan Prettyman's "Hello" (Virgin, No. 27, 18,000).

Sales this week are up 1.9% from last week's sales at 7.5 million units. Sales are down 8.1% compared to the same week last year.