At this point, I'm definitely buying a Wii U, but the PS4 is still a maybe/maybe not possibility.
For a first reveal, what we saw of PS4 today was promising, but none of the games really leap out at me yet. (Kinda like the Wii U before Bayonetta 2 and "X" were revealed)
Maybe a next gen Uncharted will sell me on it, we'll see.