If the first two days of Bonnaroo 2008 featured some of the heaviest rock bands ever to play the seven-year-old festival, the final day of music was a relatively sedate one focusing on American roots,

If the first two days of Bonnaroo 2008 featured some of the heaviest rock bands ever to play the seven-year-old festival, the final day of music was a relatively sedate one focusing on American roots, blues and soul music. Ironically, it was Robert Plant, a British rock god, who was at the center of that salute to all things Americana.

The Led Zeppelin frontman's performance with angel-voiced songbird Alison Krauss was an elegant, sultry and at times clever celebration of American roots music that also featured noted producer/solo artist T Bone Burnett, who helmed Krauss and Plant's new duo album, "Raising Sand."

Regularly flashing the stage presence that made him a rock icon, Plant was almost in character throughout, flirting and teasing the crowd, none more so than on an erotic, glacial rendering of Zeppelin's "Black Dog." Each time he just barely raised his voice, or whenever Burnett and the other players cranked up the volume, fans shouted their approval, hungry for some of the raucous energy of Zeppelin.

Throughout, Plant, Krauss and even Burnett shared the mic, dipping into the two singers' back catalog (including Krauss' "Down to the River to Pray" from the "O Brother, Where Art Thou?" soundtrack, and Plant's "In the Mood").

On one of the festival's smaller stages earlier in the day, Plant hero Solomon Burke, the so-called King of Soul, took his tent audience to church, from a throne-like chair at center stage. Following a set from pedal-steel phenom Robert Randolph, the massive singer roared, teasing the smiling faces on the other side of the barricade with a medley of soul favorites "Mustang Sally" and "(Sittin' On) the Dock of the Bay."

While Sunday featured a surplus of singer/songwriters in Pat Green, Jakob Dylan, Serena Ryder and Aimee Mann, O.A.R. united thousands for a late-afternoon set, as Broken Social Scene and Derek Trucks and Susan Tedeschi also hit the tents.

After an epic late-night, electric set just hours before, ex-Grateful Dead bassist Phil Lesh and his latest band -- featuring vocalists/guitarists Jackie Greene, Larry Campbell and Teresa Williams -- performed a small acoustic set laced with Dead favorites, including "Deal" and opener "Friend of the Devil." Meanwhile on the main stage, Yonder Mountain String Band lent the day a heavy dose of modern bluegrass.

Sunday wasn't exclusively devoted to roots music, of course, as the celebrated Senegalese Afro-cuban group Orchestra Baobab made its Bonnaroo debut (bring a saxophone-toting fan onstage to jam with the group), alongside Death Cab For Cutie and English electro/rock act Ladytron.

Traditionally, artists playing the last day of Bonnaroo face thinner crowds as fans begin making their journeys home. Sunday acts like Rogue Wave, the Lee Boys and Israel Vibration suffered this worse than usual as a result of the delayed main-stage set by Kanye West in the wee hours of Sunday morning.

Triggering a rare fan backlash at the normally cheerful Bonnaroo, West delayed his set for almost two hours, not taking the main stage until 4:30 a.m. Organizers laid part of the blame on the fact that Pearl Jam played past its curfew on the main stage, meaning it took longer to clear the area and set up again for West.

After featuring two massive rock bands in Metallica and Pearl Jam on the previous two nights, Sunday's headline slot went to Bonnaroo regulars Widespread Panic, who per tradition ended the festival by bringing it back to its jam-band roots.

For additional Bonnaroo coverage, visit the Billboard blog at JadedInsider.com.