600$ pc build

That all looks pretty good, the only thing I'm iffy on is IIRC the Corsair CX series isn't that great of a PSU. It's -ok-, but it's a lower-tier make and for something that connects to everything - should it fail - it could do some damage to your system.

You can get a Seasonic 620w for about $80ish (the M12II, 80+ bronze, 620w, full modular) which would be a much more 'solid' psu. Beyond that, looks pretty good.
 
3 good monitors for the price, The VX2270S has a panel which has excellent picture quality but somewhat bad response time. (I have this monitor but but the motion blur is near unnoticable unless you're playing serious CS:GO or any FPS Shooters)

In that case the either the viewsonic VX or the BenQ monitor should be good ones to consider.

PCPartPicker part list / Price breakdown by merchant

Monitor: ViewSonic VX2270Smh-LED 22.0" Monitor ($139.99 @ Amazon)
Monitor: ViewSonic VX2252MH 60Hz 21.5" Monitor ($139.97 @ B&H)
Monitor: BenQ GL2460HM 60Hz 24.0" Monitor ($139.93 @ B&H)
Keyboard: Logitech K120 Wired Standard Keyboard ($6.99 @ NCIX US)
Mouse: Cobra E-Blue Mazer Wireless Laser Mouse ($22.99 @ Newegg)
Total: $449.87
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-05-13 22:46 EDT-0400
 
Why would you go with three different monitors? They might have slightly different colors. I'd say choose one good monitor and get three of them so that color, brightness, etc. is more uniform across the three

Edit: Wrong thread, thought this was one where someone was looking for three monitors at once. My bad