Alan Jackson's Good Time debuts in the top spot on Nielsen SoundScan's list of the nation's best-selling albums. So why does the country music veteran have reason to be disappointed? For the same reason that Janet Jackson, who debuted at #1 last week with Discipline, probably had mixed feelings about that week's numbers.

Good Time posted a lower opening week sales tally than Alan Jackson's last album, Like Red On A Rose, which debuted at #4 in 2006 with sales of 149,000. Likewise, Discipline opened with a lower sales tally than either of Janet Jackson's last two albums, Damita Jo and 20 Y.O., both of which bowed at #2. In January, Radiohead had a lower total in its first week at #1 with In Rainbows than the band had achieved with its two previous studio albums, Amnesiac and Hail To The Thief, which opened at #2 and #3, respectively.

There were four similar cases last year, when The Notorious B.I.G., Musiq Soulchild, Toby Keith and Common debuted at #1 with sales tallies that were lower than their previous albums--all of which had opened below the top spot.

Any time an artist debuts at #1, there is cause for celebration. But the traditional cake-and-champagne parties are bound to be a bit muted when the news is mixed like this. So what's going on?

Sometimes, the calendar plays a part. The previous albums by The Notorious B.I.G. and Musiq Soulchild were released in the peak December sales season. The subsequent albums came out in March, when sales are slower. (There's just not as much pressure to buy Easter presents.)

In part, it's due to a declining sales market. Sales, as you know, have been off for several years. But some albums still manage to get off to boffo starts. In just the 20 weeks I've been writing this blog, seven albums have opened with sales of 350,000 copies or more. The biggest out of-the-box winners of this period are (in descending order of potency): Alicia Keys' As I Am (742,000), Eagles' Long Road Out Of Eden (711,000), Mary J. Blige's Growing Pains (629,000), Carrie Underwood's Carnival Ride (527,000), Jay-Z's American Gangster (425,000), Jack Johnson's Sleep Through The Static (375,000) and Garth Brooks' The Ultimate Hits (352,000).

We'll have a good test of the market in two weeks when Mariah Carey debuts with E=MC2. Carey's last album, The Emancipation Of Mimi, opened with sales of 404,000 on its way to becoming the #1 album of 2005. If Carey doesn't open with sales of at least 350,000, that will be widely read as a bad sign for the health of the industry. (No pressure, Mariah, you just have an entire industry riding on you.)

Turning our attention back to Alan Jackson, Good Time is the perennial white-hatter's fourth #1 album. Only three other country artists have amassed as many #1 albums in the 52-year history of Billboard's weekly album chart. Garth Brooks leads all comers with eight. Tim McGraw and Kenny Chesney have also had four. Jackson first topped the big chart in 2002 with Drive, which included his 9/11 rumination, "Where Were You (When The World Stopped Turning)." He returned to the top spot the following year with the modestly-titled Greatest Hits Volume II And Some Other Stuff and in 2004 with What I Do.

Usher's "Love In This Club" is #1 on Hot Digital Tracks for the second straight week, just barely fending off a challenge from Jeff Buckley's "Hallelujah," which was a mere 26 downloads behind. The track is from Buckley's 1995 album, Grace. The resurgence is due to the Leonard Cohen song being performed last week by a contestant on American Idol. Buckley, the son of Tim Buckley, drowned in 1997 at age 30.

"Low" by Flo Rida featuring T-Pain this week surpasses "Crank That Soulja Boy" by Soulja Boy Tell ‘Em as the most downloaded track of all time. "Low" has rung up sales of 3,206,000 downloads, 38,000 more than the old title-holder. Both are still adding to their totals. "Low" slips to #5 on this week's Hot Digital Tracks chart. "Soulja Boy" inches back up to #40.

Here's the low-down on this week's top 10 albums.

1. Alan Jackson, Good Time, 119,000. This is the first country album to debut at #1 since Carrie Underwood's Carnival Ride in November-unless you count Eagles' multi-format smash Long Road Out Of Eden as a country album. Discounting a pair of holiday albums, this is Jackson's 15thconsecutive album to reach the top 20. Jackson's "Small Town Southern Man" leaps from #187 to #96 on Hot Digital Tracks.

2. Jack Johnson, Sleep Through The Static, 65,000. Johnson moves up a notch in his fifth week in the top three. Johnson's album has sold 816,000 copies to date, the most of any album in 2008.

3. Janet Jackson, Discipline, 57,000. In its second week, Jackson's sales drop by 67%--the steepest percentage decline of any album in the top 100. Even so, her single "Feedback" remains in the top 10 on Hot Digital Tracks. I pointed out last week that Janet has now had more #1 albums than brother Michael. That's true, but let me add that Michael is still ahead of his kid sister in terms of top 10 albums-if you combine his seven top 10 solo albums and the six he had as part of the Jackson 5 and later the Jacksons. (Janet has had nine.)

4. Flogging Molly, Float, 48,000. This is the Celtic rock band's highest-charting album to date. Within A Mile Of Home, the 2004 follow-up to the band's 2002 breakthrough album, Drunken Lullabies, reached #20.

5. Black Crowes, Warpaint, 46,000. This is the band's first top 10 album since The Southern Harmony And Musical Companion, which debuted at #1 in 1992. (Warpaint is the band's first studio release in seven years.)

6. Erykah Badu, New Amerykah Part One (4^th World War), 41,000. Badu's album slips from its #2 ranking last week, with a 67% drop in sales volume. That's just a shade less than Janet Jackson's percentage loss.

7. Sara Bareilles, Little Voice, 39,000. Bareilles jumps from #9 to #7, matching the album's peak position from two weeks ago. "Love Song" continues in the top five on Hot Digital Tracks for the 13th consecutive week.

8. Alicia Keys, As I Am, 38,000. Keys' album has sold 3,245,000 copies to date, more than any other album in the top 20. The lead single, "No One" is #8 on the all-time Digital Tracks chart.

9. Taylor Swift, Taylor Swift, 32,000. Swift's album has been on the chart for 72 weeks, longer than any other album in the top 30. "Picture To Burn," the latest single from the album, jumps from #109 to #74 on Hot Digital Tracks.

10. Amy Winehouse, Back To Black, 31,000. Winehouse's album completes a full year on the chart. It has placed in the top 10 for 16 of those weeks-12 last year and four since its strong showing at last month's Grammy Awards.

Four albums drop out of the top 10 this week. Webbie's Savage Life 2 falls from #4 to #11, Miley Cyrus' Hannah Montana 2: Meet Miley Cyrus drops from #6 to #14, the Once soundtrack falls from #7 to #15, and the Juno soundtrack drops from #8 to #17. This is the first time since November that no movie or TV soundtracks have appeared in the top 10.

Michael Jackson's Thriller 25 sold 44,000 copies and would have ranked #6 for the week if catalog albums were listed alongside current albums. This is the fourth week in a row that Jackson would have had a berth in the top 10 on the big chart. Thriller 25 has sold 328,000 copies to date, which makes it #9 for the year to date.

Another catalog album, I Can Only Imagine, Platinum Edition opens with sales of 27,000 copies. It would have placed #15 on the big chart if it had been allowed to compete there. This is an expanded version of Time-Life's 2004 release I Can Only Imagine: Ultimate Power Anthems Of The Christian Faith, which reached #49. That two-CD collection included 22 tracks. This three-CD set features 30 tracks. (It's one thing for Billboard and Nielsen/SoundScan to tell Michael Jackson "I'm sorry, but your album doesn't meet our chart criteria," but it takes nerve to say "rules are rules" to God.)

Michael McDonald's Soul Speak opens at #12. This is McDonald's third collection of R&B covers in the past five years. All have made the top 15. McDonald, the former leader of the Doobie Brothers, began down this road with 2003's Motown, which reached #14. Motown Two hit #9 the following year. Like fellow pop veterans Rod Stewart and Barry Manilow, McDonald is finding consistent commercial success, if not necessarily deep artistic fulfillment, in carefully-targeted albums of covers.

Jackson Browne places in the top 30 for the first time in more than two decades as Solo Acoustic Vol. 2 opens at #24. It's his best showing since Lives In The Balance hit #23 in 1986. Solo Acoustic Vol. 2 has far outdistanced Browne's Solo Acoustic Vol. 1, which hit #55 in 2005. Browne's debut album, widely known as Saturate Before Using but actually titled Jackson Browne, hit the charts 36 years ago this month.

Follow-up: Jordin Sparks' eponymous debut album jumps from #49 to #34. The album has sold 555,000 copies to date-a little more than twice as many as the debut by Blake Lewis, who was runner-up to Sparks on Season 6 of American Idol. Lewis' Audio Day Dream, which re-enters the chart this week at #154 following his performance last week on Idol, has sold 274,000 copies to date.

Biggest Increase: Eddie Vedder's Into The Wild soundtrack jumps from #168 to #79 in the wake of the film's release on DVD. Sales of the soundtrack jumped by 98%, the biggest percentage increase of any non-debuting album. Vedder's haunting score was ignored by Oscar voters, which does not reflect well on Oscar voters.

Biggest Drop: The Little Mermaid cast album plummets from #26 to #176 in its second week. That's a drop of 79% of its sales volume, the biggest of any album in the top 200. The album debuted so high last week because Walt Disney Records fulfilled pre-orders that it had been taking from theater-goers who had attended performances of Mermaid, back to when it was in a try-out run in Denver last year. According to Billboard, pre-orders of an album register as sales with Nielsen SoundScan when they are fulfilled to the customer. (I have now bold-faced Walt Disney and God in the same column. Top that, Liz Smith!)

Heads Up: Next week, look for debuts by the Now 27 compilation as well as the latest from former chart toppers Snoop Dogg and Rick Ross, as well as American Idol judge Randy Jackson.

Happy St. Patrick's Day: Sixty years ago, Bing Crosby hit #1 with St. Patrick's Day, a collection of famous Irish songs such as "When Irish Eyes Are Smiling." Crosby wasn't Irish (he was born in Tacoma, Wash.), but Irish acts have since come into their own. U2 and Sinead O'Connor paved the way for Glen Hansard and Marketa Irglova, who walked off with an Oscar last month for Best Song. Must be the luck o' the Irish.