For me it's Mario Kart 8. I'm cautiously excited for Watch_Dogs, but like others said, my hype died the second it was delayed.

MK8, my hyped for Watch Dogs died when it was delayed.

Mario Kart though i am still looking forward to Watch Dogs

Not a good comparison, only a very few here will even consider getting both(wat i mean is console warzzzzzz!!!). Me i obviously pick MK8, but definitely will pick up Watchdogs in the holiday!

Watch Dogs is unproven.

Mario Kart 8, getting Watch Dogs on my PS4, which I dont have yet, so I'm only gonna be able to play MK8. 

Mario Kart 8.

It was a close call a while ago before the Watch Dogs delays and then extra delay of the Wii U version, and now with the embargoed reviews until launch, I'm wary.

Mario kart 8. We can all play that together.
Watch dogs feels like an average GTA clone after the last gameplay footage. Maybe a couple of good reviews can still sway me.

MK8 but it will have to wait until I finished Watch Dogs.

I'm getting both day 1, MK8 along my brand new Wii U, but I think Watch Dogs is more exciting. MK8 will be the same as always, which is good, but still.