Announced two days ago, the Wii U Deluxe Set is already sold out at Gamestop. No worries though, you can always pre-order the basic set. However, Best Buy seems to have sold out of both versions. Either way, it looks like the Wii U is going to be a very hot item this holiday season, and you might not want to hold off any longer if you want a system at launch.
Update: Looks like Target, Kmart, and Toys R Us are not taking anymore pre orders for the Wii U. Some good news though, Walmart is still taking pre orders for the Wii U Solution Bundle, which includes a copy of New Super Mario Bros. U.