Pelileu, okinawa, Marshall islands, marianas islands, Philippines, Singapore, makin island, battan death march, coral sea, wake island, new guinea, guadalcanal, midway, hell the Japanese even invaded some of the aleutian islands of Alaska. There are so many interesting campaigns and battles. For whatever reason the pacific never gets the attention Europe gets on the western front. Even more brutal and terrible with even less coverage was the war on the eastern front.
In my opinion some of the more interesting events of the war in the pacific is the USS Indianapolis (how it was almost torpedoed before it delivered the atomic bomb, and the tragedy as it was later sunk on its return.
Or just some of the sheer luck and decisions involved in the battle of midway (including cracking the Japanese code)