Hitman Absolution is released within few hours and Assassin's Creed 3 is out on PC in 2 days, so..
What do you think?

Why not buy both? Oh, and Dishonored while you're at it.

I have Dishonored and I got only time for one game more now and it's between those two as I will 100% buy Far Cry 3 next week already.

Then you're in a tougher situation. I'd go for AC3, playing as Connor looks awesome.