1) I really hate multi-monitor setups for gaming, but frankly you have to experience it for yourself.
2) Uh, 2x1080p??
That's horrible as the gap would be in the MIDDLE of your viewing experience.
3) Cheap 900p monitors?
The quality of the monitor strongly affects gaming, and if three 900p monitors are cheaper than a single 22" I wonder how good they are.
4) *Frankly it's hard to say without a budget but my advice is usually a single, high-res monitor.
2560x1440, IPS, 4ms, 60Hz->
http://pcpartpicker.com/part/acer-monitor-umkg7aa002
2560x1080, IPS, 5ms, 60Hz->
http://pcpartpicker.com/part/lg-monitor-25um56p
1920x1080, IPS, 5ms, 60Hz (27")->
http://pcpartpicker.com/part/aoc-monitor-i2757fh
Those are only examples.