Masashi Kishimoto came up with narutos name while eating ramen, and based Naruto's backstory on his own past experience as a child.
The names of the three Sannin (Jiraiya, Tsunade, and Orochimaru) were taken from the "Legend of the Gallant Jiraiya" each of whom had a special magic they learned - toad, slug, and snake.
The scene where Konohamaru and Naruto go into an adult magazine store for 'inspiration' was never in the manga.
The reason the ninjas all wear protective headbands is because Naruto originally wore goggles (first episode), but the artist of the manga thought it took too long to draw the goggles, so he replaced them with the forehead protector.
Chouji's dad, Choza, is actually one of the ninjas that want Naruto dead in the first chapter (pay attention to page 37, chapter 1)