For games that I will buy within the first 24 hours have to be (in order of relevance)
Super Smash Bros - Without a doubt this game will be day one purchased.
Mass Effect - if t hey were to release a new one
Elder Scrolls
Zelda - although I still haven't beat skyward sword I will before the new one launches.
The Witcher - I only played a beat the Witcher 2 but that's enough for me to make this a day one purchase
3D Metroid - Because the Primes were amazing.
Any great JRPG that coms out on Wii U - Lets be honest this will happen once in a lifetime.