One of this year's most anticipated sets is the Lego Harry Potter Diagon Alley (75978)! The set is slated to be announced on by Lego early Monday morning here on the East Coast! If you click on the image or the link you can go and keep track of the countdown for the official announcement.
What we know so far:
Some initial reports indicate that the set will contain the following shops from the films: Ollivanders Wand Shop, Scribbulus Writing Implements, Quality Quidditch Supplies, The Daily Prophet, Flourish & Blotts Bookseller, Florean Fortescue’s Ice Cream Parlor, Weasleys’ Wizard Wheezes and Knockturn Alley.
From what I can guess, contrary to the last Diagon Alley (10217) that was released in 2011, this will probably be more in the style of the Lego City Main Square (60271) with partially finished structures instead of the larger nearly-complete models we saw in the past rendition. I'm only guessing this due to the number of structures we're getting compared to previous sets.
As a fan of Harry Potter myself I'm excited to see this announcement on 8/31!