According to one user who has received their copy of Destiny a little ahead of time, he/she has posted images of the cover art of Imgur and according to one of the photos, it shows that the game could take up as much as 40GB on your console in order to play it. For those who have preloaded the game, you might have noticed that it has only taken 18GB.
This is far from the 40GB of storage that has been suggested on the box. There is a good chance that the 40GB storage could be the recommended storage space for save files and other content that the game might require for installation. There is also the possibility that the 18GB install on the Xbox One might only be enough to run the game at the start and that additional content will be downloaded while you play.
Either way for those who are worried that Destiny might not have enough content, it is safe to say that 40GB would seem to suggest that Bungie has a lot of content prepped for the game that they might not have shown off in the alpha and beta releases, but either way we’ll keep our eyes peeled for more information.