I used 3 screens for over a year until very recently.
Asus 144 hz 24" VG248QE, which were pretty much the best TN panel you could get for gaming under 27", especially for FPS games. I just didn't have the space or the proper stand/mount for 27" at the time. I ran 680 4gb FTW+ in SLI on a 3930k CPU system. I usually kept my FPS at 143/max unless I turned the environmental reflection setting higher than 2/3 - the top two notches really smoke the FPS performance.
Now I'm using a 27" Asus IPS 1440P panel. I'm driving it with a 4930k and an eVGA 780 Superclock card which is overclocked a bit, and it's performs nearly the same as my Titan video card I tried earlier, for about 300$ less as well. The 4930k isn't much, if at all faster than the 3930k chip IMO for games, but it was only 10$ more than a 3930k CPU now, so wth. I get max FPS with the same max settings with reflections on 2/3 or so, always at 60 in AH. I'm just trying to find a desk and mount to add the other 2 IPS panels, as my older 24" set up just barely fit, so it's either a new room for the setup (wife ack extreme, like 100 88 guns and 1000 37mm at once), or moving some other stuff out of current room, and buying a new larger desk (wife ack again as current 2000$ desk was xmas present from her). I'll figure something out before xmas, and have 3 IPS 27" running, and will probably need to add another 780 card possibly, we'll see how the single one performs first.