so i decided to build a gaming pc so im going with
case: zalman z11
motherboard : asrock z68 extreme 4 gen 3
cpu : i5 2500k
hdd: wd 500gb caviar blue aakx
ram : 2*4gb corsair 1600mhz
gpu: zotac gts 450
psu : i didn't choose one !
so plz help me with this
Please do fill in that form in cranked's link. You'll need a more powerful gfx card and a less powerful CPU for your budget for gaming. Games are mostly bottlenecked by GPU's and not CPU's.
Difficult to suggest builds without knowing the exact usage, but something along the likes of a $150 AMD quad and a $250 GPU seems to me to be the right balance for the $500 you seem to have specified for CPU+GPU. Also, I don't see the need for a $200 board. All you'll need is a cheaper AM3+ mobo IMO
Specific recommendations only after you've filled us in with specific info