if you get digital games, and find a white 50$ cheaper than the black, get it. a black wii U will need an HDD anyway, so use the 50$ extra money to get the HDD.
Buy also a pro-controller, is in my top 3 best controllers ever and the games will need it, more than wiimotes.
Games:
-DKCTF - is pure love, my favorite game.
-Bayonetta 1&2,2 great games in a single pack.
-Mario kart 8 is the best MK game, and it will soon get better, the 12$ DLC with half content of full game and the 200c DLC is a great adiction.
-Smash bros for those who like it. I personally find this smash bros with the best gameplay, roster and multiplayer.
-Mario 3D world is a great game.
And the must have upcoming games:
-Seems that you like jRPGs, so, you cant miss xenoblade X. xenoblade is one of the best jRPGs ever created. and this seems to be even better, adding new gameplay features, dolls for even more exploration, a bigger world, and non linearity.
-zelda
im also not mentioning lots of good value games.