I just bought an LG 27" 27UD58. It's a 4k IPS monitor and the only one that I could find for <$500. I have been thrilled so far. I briefly thought about going to a 21:9 setup, but it seemed more advantageous to those that do video editing, or other work that would benefit from a larger workflow space. As for the LG, like I said I am really happy. Even though I don't do anything that requires color accuracy, it is pretty spot on. I am an ISF calibrator (although I have not calibrated a TV or projector in years), so even though I have not thrown a colorimeter on it I can tell that is well within expected tolerances for what you would expect. There are definitely better monitors out there, but for what I need, it was perfect.
One slight annoyance; all the icons got really tiny! Easy fix for windows, but Steam popups are still unreadable. If someone has a fix, fill me in.