I have two PC's and know one needs an upgrade more than the other, but I also am happy to know that if I upgrade my one PC, the other will get some decent hand-me down parts. Here are the specs of the two PC's
http://pcpartpicker.com/p/32SQn - The Stronger PC
http://pcpartpicker.com/p/32T0j - Not as strong, but has been a great PC
Don't judge me on either PC's parts, I did what I could with the money I had on the first one, and the second one I got the whole thing when all those parts were fairly new (before the gtx 7xx series and before Haswell) and got them for less than $400.
Now that I've said that, my nicer PC I have an ACER h236hl bid IPS monitor that I love, but on the other computer I have a monitor that basically my friend gave to me, but I don't intend on keeping it, I want to give it back, also, it's TN and I love IPS so I would like to upgrade with that, and if i was to upgrade, i'd probably get a 27" 1080p IPS monitor because i think 1080p looks fine on a 27", and I know I couldn't handle 1440p. I would obviously take the 23" to my other computer, and give my friend his monitor back. The other option is, I get a gtx 760, and give the 7870 to my other PC. I have $400, and am looking for recommendations, feel free to recommend things other than what i've said, and feel free to recommend I simply save up for something. Thanks in advance to anyone that helps. :)