Maybe I'm just being nostalgic, but some of my all-time favorite gaming experiences have occurred while playing a Nintendo system. The first Pikmen game, Pokemon Red, Super Smash Bros., most Super Mario games; they're all Nintendo and they're all great.
The Wii U will bring new IP's with tons of potential (like The Wonderful 101) along with epic sequels of fan favorites (i.e. Pikmen 3). With time, there'll be new Zelda, Metroid, and Super Smash Bros. games.
While it may not be as powerful as future Sony or Microsoft consoles (we don't know yet), it is certainly a step above the current generation of consoles. As long as the Wii U gamepad doesn't become a gimmick (like the Kinect), it has a chance of becoming something great. Currently, the Wii U can only support one gamepad per console (but you can still use Wii controllers, the Wii U pro controller, and others), but eventually that number will grow.
WiiTV will finally bring a great media center to a Nintendo system. Nintendo is also finally fully embracing online gaming. Despite my excitement, I do still REALLY wish that the Wii U was called basically anything else, but I won't allow such a minute criticism bring me down.