What does a little piece of heaven mean?

Answer 1

Everyone is always trying to read into some deeper meaning of this song, but in fact, it is quite literal. Following is the explanation from the band members.

This song, formerly titled 'Big Bear' was another song written by The Rev. It is the longest track that features on the latest album, and includes a variety of instruments (such as violins, cellos, trombones, clarinets, saxophones and trumpets, plus a choir of singers) to achieve its 'rock Horror Opera' effect. It also features a guest singer named Julia, who sings the part of the main female 'character', as well as The Rev doing part lead vocals, and Zacky playing the role of the 'minister.' "It's basically a story about a man murdering his significant other and preserving her to do whatever he pleases with her. And the story takes a twist," Zacky Vengeance explains, with M. Shadows adding, "She comes back from the grave and kills him." Zacky mentions they then, "go on this murderous rampage." "They're both dead souls together and get married and terrorize everyone else," Shadows concludes.

Answer 2

It means something really enjoyable. It's often used in a sarcastic or ironic sense: "Well, aren't you just a little piece of heaven" for someone who's being troublesome or gloomy.