Avenged Sevenfold formed in 1999 in Huntington Beach, California while the members were still in high school. The band uses pseudonyms, and call themselves M.Shadows (vocals), Synyster Gates(guitar), Zacky Vengenace (guitar), Johnny Christ (bass) and The Reverend (drums).
Metalcore:

Avenged Sevenfold released their first full-length CD Sounding The Seventh Trumpet in 2001. Their sound was metalcore,combining hardcore and heavy metal. In 2003 they released Waking The Fallen which was still metalcore, but started leaning a bit more toward the metal side.
Major Label Success:

In 2005 the band signed to major label Warner Brothers and released City Of Evil. It completed their evolution to an almost exclusively metal band, with this album containing classic and thrash metal influences. 2007 saw the release of their self-titled album, which saw them move even further toward the mainstream.

In December, 2009, the band's drummer Jimmy "The Rev" Sullivan passed away. Avenged Sevenfold announced that Dream Theater drummer Mike Portnoy would record the drum parts for the band's next CD.
Current Members:

M. Shadows - Vocals
Synyster Gates - Guitar
Zacky Vengeance - Guitar
Johnny Christ - Bass
Jimmy "The Rev" Sullivan - Drums (RIP December, 2009)
Discography:

2001 Warmness On The Soul EP (Goodlife Recordings)
2002 Sounding The Seventh Trumpet (Hopeless)
2003 Walking The Fallen (Hopeless)
2005 City Of Evil (Warner Brothers)
2007 Avenged Sevenfold (Warner Brothers)