I plan to install a second 140mm on the top blowing out and two 120mm's on the bottom blowing in.
Would this provide good circulation for a cooler system and should i install a side fan or a better heatsink such as a Zalman 9900?
My setup is-
-Intel i7-920 (May be overclocked slightly once i am sure i want to and know how to)
-ATI Radeon HD 5850 (May Crossfire in the future)
-Asus P6T Motherboard
-OCZ 3 x 2gb 1600 DDR3
Are these enough fans to cool my system and does my setup provide good circulation? and also is the 750w a good choice since i may want to crossfire in the future?