Don't know your budget but I'd probably go with an Antec P182 case to start with and good power supply. It has lots of room and takes lots of fans and is good for cooling.
Since it's for gaming you may want to overclock, so I'd go with Intel and the quad 6600 is good bang for the buck.
I don't know which motherboard to choose but maybe something like this.
http://www.ncix.com/products/index.p...nufacture=eVGA
I'd go over to the NCIX forms and read what other peoples builds are and post your build so others will comment on it.