Nice beginning. The main thing I noticed is the two exhaust fans on the back of the cabinet both appear to be facing outward (or maybe that's inward, can't remember what direction fans blow -toward or away from label side). I would recommend having the bottom fan be the intake fan and the upper fan the exhaust (exit) fan. This way the air will actually flow in and back out.
Also, it wouldn't hurt to perhaps add another fan or two with the same air flow properties. The cooler the computer/monitor the longer they last!