FOO Fighters, Muse, Soundgarden, Black Sabbath with Ozzy Osbourne, Tool, Red Hot Chili Peppers, System of a Down – just some of the bands being mentioned on music forums as possible 2011 Sonisphere Festival headliners.

Speculation has already begun over who might headline next summer’s hard rock and metal event in the grounds of Knebworth House.

Veteran shock-rocker Alice Cooper topped the bill this year on the new Friday night of music, performing at a British outdoor festival for the first time in nearly 30 years.

German industrial metallers Rammstein and British heavy metal icons Iron Maiden, who released new album The Final Frontier this week, stole the show on the main Apollo stage on the Saturday and Sunday respectively, as the UK festival sold out for the first time in only its second year.

Sonisphere organisers are keeping tight-lipped over who is on their wish list for next July’s three-day festival.

However, John Jackson, who created the international touring festival with Stuart Galbraith and is also the booking agent for Metallica and Iron Maiden, let slip that Slipknot’s Corey Taylor could well return to Knebworth for a third year in a row.

Corey could appear with either Slipknot or Stone Sour, who have both played European Sonisphere dates over the past two years.

When asked at a press conference who might headline next year, John Jackson said: “We can’t say just yet, but we have some ideas.”

He added: “Corey Taylor announced that he’d see everyone next year.

“Now he’s got two other bands [Slipknot and Stone Sour]. I’ll leave that for you to guess... or it could be both!”

Already a fan of the Sonisphere experience, Corey Taylor played a blinding acoustic set on the Bohemia stage on the Saturday evening.

The tent was bursting at the seams as fans clamoured to see the Slipknot and Stone Sour frontman armed with just a guitar.

He opened his solo spot with a cover of Elton John’s Tiny Dancer before playing Bother, as well as Chris Isaak’s Wicked Game and Nirvana track Polly.

Taylor also poignantly dedicated Slipknot song Snuff to former bandmate Paul Gray, who recently died.