Hey, I love BOC's "Godzilla" as much as anyone (except maybe Mr. Owari himself). It's the song the proved rock n roll and giant monsters go together naturally. And then I discovered all sorts of bands that sang about monsters, or took their names from monster movies. Not all of them are metal, either.
Here's my favorite of the bunch, one I discovered only recently. This is the second recording of it, with a slightly heavier sound. I'm not completely familiar with the Ghoulies, as they have had quite the history. I would have loved discovering them back in the 80s though. They cover a wide variety of songs, but this is one of their originals.