On my birthday, what Godzilla movies should I watch?

If I were to spend a day watching Godzilla movies it would absolutely be Monster Zero, Terror of MechaGodzilla and Godzilla, Mothra, King Ghidorah: Giant Monsters All-Out Attack.

After that, if I'm not exhausted of watching movies by then, it would depend on my mood. Lately I've had an interest in revisiting Godzilla 2000. So maybe that.

Happy early Birthday!

For me, I have watched most G movies out of order. The only series I have seen in order so far is the current one with 2014, Kong Skull Island and KOTM. So I guess that would be my recommendation. After watching a marathon, I noticed the ones I enjoyed most were the TOHO ones if that is any help.

Thanks!

I own and have watched all the Godzilla movies, but I don't think I've ever watched them in order either, (except for the newest ones). So maybe I'll try a few in order and see if that adds to the viewing experience. 

Would you prefer a theme, or characteristic ,maybe a variety of some kind?

I think you have the some of the best of the best with 54, Monster Zero, Terror of Mechagodzilla, Godzilla vs Biollante, and GMK.