http://www.joystiq.com/2011/06/07/wii-u-is-1080p-has-hdmi-out-internal-flash-memory-sd-and-usb/
While Nintendo was blowing minds this morning with the announcement of its new console, the Wii U, the company's Japanese press site was quietly releasing all the juicy specs of the upcoming machine that we hunger for. As mentioned during the presser, the console will output games in high definition, now revealed as ranging from 480i to 1080p. Moreover, the Wii U will output HD by employing HDMI.
As far as internal storage goes, it's still unclear whether or not the Wii U will come packed with an HDD, but the specs sheet does amorphously detail "internal flash storage," as well as an SD slot and the ability to use USB storage. Notably, the list points out that the USB storage will allow for external HDDs. And while the disc slot gives us the impression that Wii U games will be disc-based, Nintendo has yet to reveal its medium of choice.
For anyone in doubt as to whether it's a new console or not (wodmarch, I'm looking at you :P). So there we are, the hardware will support 1080p but my prediction is still that most games will run at 720p. I don't even have an HDTV...