The most fun you can have with metal band names is looking for brutal death metal bands. Abominable Putridy, Decrepit Birth, Vomit Remnants are some of my favourites. The music can be a bit questionable, but the names are great.
No, no, no. Opeth goes into the scary bin too. Blackwater Park is the stuff of nightmares! Megadeth are fine though, Dave has a lot of fun things to say.