As I said, if you’ve been waiting for a new Wii, the Wii U will certainly make you happy. If not, then as of right now, this is a definite leader, with initial sales eclipsing both the initial runs of the Xbox 360 and the PS3. However, you have to consider, with new entries from Microsoft and Sony on the way within a year (reportedly), the risk of obsolescence is pretty high unless the GamePad innovations really take off.
But even if they don’t, worst case, you get a very new and different experience in gaming.
Plus the kids will love it.