I have a HUGE bias in favor of this particular entry in the series because, like many others here, it was my first exposure to Godzilla. I have to admit that, at the tender age of 6, I was totally blown away. In fact, I was so enamoured with the film that I drew like a 6 or 7 page picture book of the movie that I brought to my first grade class the following week for Show & Tell. (Sure wish my mom had kept that, dang it!) I remember that I didn't know how to spell "monster" so I abbeviated it to "MR"

That the film debuted the same year that I did also makes it special for me.
Anyhow, this movie is just all kinds of awesome fun. I was instantly hooked because, for the first time, I saw a movie monster who had PERSONALITY. He wasn't just another rampaging whatsit like many of Harryhausen's early creature feature creatures (sorry, Ray). This big dinosaur guy could fight like nobody's business (whoa, he has dragon-ish breath! Cool!!) and was cool, but kind of grumpy, too! He had a name that all the human people knew, so he must've been important! And even though he didn't show up for like half the movie, it seemed they were always talking about him. The giant bug thingy had a real name, too, and was worshipped as some kind of god, which was pretty unique and cool. And I thought the human plot in itself was interesting enough to keep me glued to the set. No easy task for a hyperactive six year old. Try that with today's six year old kids! And lastly, being a Japanese film, it just had a different look & feel to it than any of the American monster movies I had watched up to that point.
It recall it getting a pretty typical blah rating in Leonard Maltin's Film Guide for years. But then someone must have re-watched it, because the next edition upped the rating by a couple of stars and actually gave it a freshly re-written plot description: "Particularly lively entry in the series with a colorful load of castaways shipwrecked on a mysterious tropical island, threated by evil miltary types. Meanwhile, Godzilla battles a stupendous shrimp. P.S. Mothra also shows up." or something along those lines.
Anyhow, so many decades later and having seen all of the other Showa, Heisei and Millenium movies, I still just love this little film to death because it was such a refreshing change of pace from the films that came before it. The setting is cool, the cast is fun and each member gets a chance to shine, and gosh, who
didn't have a total crush on groovy Kumi Mizono??? Between her and Ultraman's Fuji, I was a smitten young lad, I tells ya!
Another thread here at MZ mentions new licensing for this movie?! I sure hope this gets
the best HD transfer source materials
AND it must have the AIP dub instead of, (or at the very least be included along with), Toho's international dub. If it's just the Toho-backed dub I'll probably pass, since I already have the Sony DVD. Without the AIP dub I cannot justify double-dipping, unless the picture is jaw-droppingly gorgeous or something, or it's only $5.