I was going to use the trailer for Godzilla vs the Smog Monster (1971) but came across the song that played over the titles. it's a cool song, done with care to sync up properly and it works well.
and a great message in the lyrics as well. this is one of the Godzilla movies I have actually seen on the big screen, back in the day. it's pretty gruesome when one thinks about the imagery in it, and yet it's aimed pretty squarely at kids. good stuff!