These days, superstar guest albums and cover records mean big business. Just look at Santana's last few releases or Rod Stewart's hugely successful Great American Songbook series. Some might think progressive country music legend Willie Nelson is just joining the fold with next week's release of American Classic, but the redhead is anything but a stranger to the concept. Nelson all but invented the trend, most notably with his influential 1978 classic Stardust, an initially discouraged collection of popular standards that became one of his most successful albums ever.

While touted as an unofficial sequel to the Booker T. Jones–produced Stardust, American Classic is more than anything a jazz album, even being released under the Blue Note Records moniker. From the opener "The Nearness of You," popularized by Glenn Miller in 1938, Nelson fronts a gifted jazz group that includes lyrical pianist Joe Sample, and proves a charmingly limited vocalist à la late-era Billie Holiday. But Nelson's voice is not grainy, remaining as clear, assured and unwavering despite his 76 years and his love for smoking weed.

Due to uniform tempo and instrumentation, the first half of the album is sadly lackluster, featuring limp renditions of the crooners "Fly Me to the Moon" and "Ain't Misbehavin'," two songs that we've been beaten over the head with too much over the years. This problem alone makes American Classic an unworthy successor to Stardust, which at the time was a novel idea.

American Classic doesn't heat up until the surprisingly charming Norah Jones duet "Baby, It's Cold Outside," which far outshines the Rod Stewart and Dolly Parton version from a few years back. It's playful and sexy (despite the obvious May-December romance implications), and you can actually hear Nelson smiling throughout. Their two voices' odd yet compelling chemistry makes further collaboration a good idea.

A sultry "Angel Eyes" keeps the excellence going, truly sounding like a lost Stardust outtake, and leads into a delicious "Since I Fell for You," featuring Jim Cox's bluesy organ and fantastic harmonica punctuating each vocal line, courtesy of longtime Nelson player Mickey Raphael. A jazzy update of "Always on My Mind" ends the record strongly with a wink and a subtle suggestion that the perennial road warrior is still fucking up in the same ways.

Nelson's sincerity and palpable reverence for the craft of others has always kept his stylistic experiments free of gimmickry, from the reggae album Countryman to last year's Two Men with the Blues with Wynton Marsalis. But here his choice of songs and the market's inundation with the idea ultimately diminish the record's potential for enjoyment as a whole.

Another guy who is no stranger to marijuana is Jamaican dancehall superstar Sean Paul, who returns this week with Imperial Blaze, his follow-up to 2005's massively successful Trinity. While his last album comprised nonstop aggressive club bangers, Sean Paul finally branches out across the 20 tracks, making Blaze his most eclectic so far. Case in point is the ballad "Pepperpot," which opens with shimmering acoustic guitar chords and features his sweetest singing to date.

The unrequited love in the lyrics is new ground for Sean Paul, a sign of maturation that reappears in "Straight from the Heart," a tribute to his mother. This hip-hop cliché (well done here in a traditional rock-steady reggae beat) is no surprise. Throughout the long and storied partnership of reggae and American rap (next up in the highly anticipated Nas and Damian "Junior Gong" Marley collaborative album), Sean Paul has merged these forms more than anyone, to the point of being completely accepted by hip-hop radio. And despite his patriotic decision to have Jamaican dancehall producers helm the album, the songs utilize too many overused American production conventions, including the familiar throbbing, blaring keyboard accompaniment on hot dance track "Press It Up" and the much-maligned Auto-Tune on "Bruk Out."

While the first single "So Fine" is not nearly as immediately catchy as past hits "Get Busy" or "Temperature," Sean Paul's wide appeal and lucid patois delivery make him a sure thing commercially. Time will tell if he'll continue to blaze an artistic trail as well.

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