1440P if you can swing it. It depends on what you do with your pc, though. Do you play games a lot? Do you watch a lot of videos, movies, Netflix, etc.?
If no, I'd wait another year for a 1440P for the prices to drop further.
I'm going to use the display mainly for web surfing and video watching.
BTW, like what I posted, what's the reasonable price range for a 27 inch 1440p display?