There's been a lot of great Godzilla appearances in his various movies. Godzilla vs the Thing, Godzilla vs the Sea Monster and Godzilla vs MechaGodzilla all spring to mind, as well as the original, though you only see his head in Godzilla, King of the Monsters in that initial appearance. Heck, even the first "reveal" for 2014's Godzilla is pretty impressive, despite all the other many flaws going on in the movie.
Here's one that's often overlooked, his "reveal" in the first issue of Marvel's great Godzilla, King of the Monsters. He's bursting forth from an iceberg, much to the surprise of the Alaskan oil field workers. Good thing the S.H.I.E.L.D. helicarrier was pretty close to Alaska at that time, since this Godzilla was pretty fearsome in that first episode. Trimpe and Mooney did an awesome job of portraying the sheer menace Godzilla could be.
To read two articles about this great green Godzilla, get the new issue of Xenorama, on sale soon!