Johann Hegg from Amon Amarth is the greatest death metal singer IMO. Especially, since his growling is quite intelligible. Christian Alvestam is also high on my list because he can sing ANYTHING!
Im sad panda now... How can you diss Lord Seth? His growls were fucking great and his clean vocals fucking pwn ass. He's not the best vocalist tech-wise but his tone is fucking great. But Mikael is way better in every way.