One of the biggest criticisms levelled against 3DS was the lack of a digital store at launch, but Nintendo president Satoru Iwata has assured investors Wii U will land with a full download store.
Iwata didn't discuss the available types of software — Virtual Console, WiiWare etc. — but did confirm that Wii U owners can choose to buy their Nintendo-published games physically or via download, right from the start:
For the Wii U, we will start the digital download sales of packaged software that I just discussed, so our consumers can choose either the packaged version or the digital download version of the same software from day one of the Wii U’s launch.
Nintendo hasn't revealed Wii U's internal storage capacity but we know it'll support USB external hard drives, so if you want to do a lot of downloading you'll likely need a HDD.
Satoru Iwata also confirmed that Wii U release date and price announcements will probably happen after E3.