Im seriously having a tough time deciding. I'm very obsessed with Zelda and never played Windwaker really. I already own NSMBU. never really played Pikman though it looks awesome and I know nothing about wii party u.
From the gamepad.
Updated with amazon current cost:
Pikman 3 - $49.33
Wwhd - $41.37
wii party u - $42.75
Nsmbu - $41.03