Honestly, none of them have anything I really care about getting yet. I am sure once the next Mario, Zelda, Metroid, ect, come out, I will want a Wii U, but that is a ways off. I am inclind to say PS4, but till we see some games can't really commit.
Last gen I got a PS3 and Wii. Both had exclusives that I really wanted. Never got an Xbox 360, because it only had one exclusive I wanted. In my personal opinion, a console should have 10 exclusives you want (and I mean can't wait) to play before you invest in getting one.