I also back
Mothra vs. Godzilla (1964) (Godzilla Vs. The Thing)
Had 2 votes in our list. Widely regarded as the best Godzilla film (89% RT rating), (although I think Godzilla Vs. the Smog Monster is better). Full interesting story, excellent music and effects.
Plus, on a side note, famous Godzilla music composer Akira Ifukube composed one of the most beautiful ballads in horror film history sung by Emi and Yumi Ito: