I love to sing some karaoke, although I am not very good.
well maybe you should try sing-along songs instead as then you don't need the lead vocalist.
but then there is no fun in that! What do you think?
Have you heard of the Diablo Swing Orchestra? They formed in 2003.
Singing
Sorry? THe line up features instruments that you don't usually see in a metal band, like a cello. 
I have not, what type of music do they do?
Metal. Like Viking metal which is black metal with influences from Nordic folk music. Not good for karaoke!
Oh okay I understand. What kind of instruments are used then?
Heavy metal genres
A number of heavy metal genres have developed since the emergence of heavy metal (often shortened to "metal") during the late 1960s and early 1970s. At times heavy metal genres may overlap or are difficult to distinguish, but they can be identified by a number of traits. They may differ in terms of: instrumentation, tempo, song structure, vocal style, lyrics, guitar playing style, drumming style, and so on.
Alternative metal.
Alternative metal is a style of heavy
released as a b-side to "I Can Hear Music", a Ronettes cover, by Larry Lurex, not long before the release of Queen's debut album. At the end there is a baby heard crying.
Lead guitarist Brian May made this statement, "And Freddie at that time said 'Write me stuff... I know I don't have very long; keep writing me words, keep giving me things I will sing, then you can do what you like with it afterwards, you know;