Best versions available of each "americanized" Godzilla film in the showa era, in order. I have them all :-)
consider the "A" option to be the best version of the US cuts.
(note: the japanese versions are all available in HD. Google is your friend.)
1. Godzilla
a. the Criterion Bluray
b. the Classic Media release (alternate special features)
2. Godzilla Raids Again
a. the US and Japanese reconstructions on myspleen
b. the Classic Media DVD
3. King King Vs Godzilla
a. The Official Universal release. Blu/DVD
b. The reconstruction of the longer japanese version on myspleen
c. The VHS rip of the even longer Japanese version on myspleen
4. Mothra Vs Godzilla
a. The AIP reconstruction on Myspleen
b. The Classic media release
5. Ghidorah The 3 Headed Monster
a. U.S. Theatrical Reconstruction on myspleen
b. The Classic Media DVD
6. Monster Zero
a.The Classic Media DVD
7. Ebirah
a. The Kraken BluRay
b. alternate TV version, reconstruction using Titra dub (coming soon to myspleen, hopefully)
c. work in progress TV version on MySpleen
8. Son of Godzilla
a. The OOP sony DVD
9. Destroy All monsters
a. The color and contrast corrected fan edit of the tokyo shock bluray
b. the OOP tokyo shock bluray
c. International Reconstruction DVD on MySpleen
10. All monsters Attack
a. The Classic Media DVD
11. Godzilla Vs the smog monster
a. Kraken BluRay
12. Godzilla vs Gigan
a. kraken Bluray
13. Godzilla Vs Megalon
a. The tokyo shock Special edition, which was recalled/never released due to Toho's objections over special features
b. the movie only tokyo shock DVD
14. Godzilla Vs Mechagodzilla
a. The OOP Sony DVD
15. Terror of MechaGodzilla
a. The Classic Media DVD