Ergo, I'd recommend 27-inch cheap IPS panel (Catleap or similar). If budget is not a concern, then a 27 or 30-inch IPS from Dell or similar.
Well, Catleaps are the only cheap 27-inch 2560x1400 panels. But they're also cheap for a reason: they're basically an LCD panel with a bezel and a power button. Only DVI compatible (I guess not a big deal), no OSD for fine tuning, no ergonomic adjustments. And they're likely to have a dead/stuck pixel. I really don't like buying a monitor where it's essentially cost/real estate above everything else.
I can't stress this enough but again this is IMHO - multi-monitor gaming is such a potential hassle, especially if you are planning to use higher than 1920 x 1200 panels. But even at that resolution, you need the horsepower of a top CPU and GPU(s) to enjoy gameplay. All in all, it's three (ideally identical) monitors, a higher-end CPU, high-end GPU(s), appropriate PSU, desk real estate, extra air-conditioning because of all the heat, inevitable frustration setting up and troubleshooting X-fire or SLI, and so on. Man am I a bummer!
Actually, many games are GPU bound, and the CPU doesn't start bottlenecking the system until you reach down to Core i3 tier performance for something like Battlefield 3. But it depends on the game. And even at 1920x1200, a GTX 660Ti or Radeon HD 78xx will do just fine at high settings, unless you're trying to aim for 60FPS all the time.
The other parts aren't really that bad. You don't need a full ATX case unless you're really strapped for space using 12"+ cards. PSU requirements aren't that bad. You don't need 1000W until you start getting into 3-GPU setups. Crossfire and SLI have basically been reduced to AFR modes (splitting the workload provides the problem) unless you fine tune it yourself. And heat... well my system was just fine when it was a staggering 95F
in my room. I wasn't running Max Payne 3 (the only game I know that will bring my cards to nearly 90C), but again, just have airflow.