Wasn't planning on buying any of them till 2014. Buuuut...
I plan on buying the PS4 purely because Sony has pretty much always had my preference in exclusives covered, in addition to said library being quite considerable over Nintendo and MS systems historically. I was going to buy it at launch, but Drive Club got delayed, Infamous isn't till 2014, and Killzone Shadowfall turned out to be more of Killzone 3 (blah) instead of Killzone 2 (which was my favorite shooter of last gen.) Launch lineup was very mediocre for me otherwise, so I'm fine waiting till 2014. Luckily I did hold out though since they announced the Vita / PS4 bundle, so I'll probably go for that.
I liked my Wii a lot, but I don't see myself buying the Wii U in the near future. Yes I love brawl, zelda, mario, and plenty of other Nintendo first party titles, but my interest faded over the years. While I bought a Wii for smash, I don't know if the new smash will be enough for the Wii U.
Never had a problem with One's old policies, and cloud computing seemed quite cool, but after all the backtracking it's pretty much the same system as the PS4. So, unfortunately, it comes down to my library preference. Unless there's a huge reason for me to play a certain game on it over my PS4 or PC, there's not much of a reason for me to buy it at all. Will happily fiddle with a friend's xbox one if I get the chance though. I've always enjoyed the user interface quite a bit. The launch lineup had literally nothing for me on the game front and, much like the PS4, I won't consider buying it till I start seeing some more games in 2014.