What is correct to say?
Korn* is a great band
Korn* are a great band.
(* You can replace your favourite band's name here)
Of course everybody there is no doubt about the following sentences:
The Beatles are a great band
Led Zeppelin is a great band
But with certain kinds of names, the situation becomes difficult.
Metallica are a great band
Metallica is a great band
Is there any consensus on this matter?