Advice New rig

[muplayer]

Im building a new gaming rig and just bought these parts:

Graphic card: Powercolor ATI Radeon HD 4870 1024MB GDDR5
Processor:Intel Core 2 Quad Q9550 LGA775 2.83GHz 12MB-cache (1333FSB)
Motherboard:Foxconn BlackOps Intel X48 (Socket 775) PCI-Express DDR3
Memory:Corsair 4GB DDR3 DHX 1333C9DHX Twin3X
PSU:Coolermaster Real Power 850w Modular Power Supply

I will be using the computer for gaming mostly, like Crysis , COD4 , World conflict etc

I need second opinion on the components and if i made a good choice buying them and will they do the job required?

 

[SGWills]

you will get people who will tell you which graphics card series you should get e.g ATI or Nvidia, other than that the components look ok, not sure on the motherboard but i havent read up on the black ops

 

[Tummy]

<Insert Other GFX Card Here> Is Better Then The One You Have.