best you go to the mac site and see what builds they have on there pro lineup then build 1 to them specs. the reason for this is that hackintosh works best with known configs and you wont need hacked drivers called kexts. hackintosh is a pain when you dont have supported hardware... i tried and failed miserably as i had to remove half the hardware in my system just to get it to boot...
infact its better not to even bother with it. just build a mac like system and get a legit copy of lion osx or similar.
more often than not macs use ati gfx cards. the last time i looked (12months or so back) they used them exclusively so you will want to check and match yours to it.
its a shame i know but macs are often a generation behind windows based builds. due to them using standardized secs for there pro builds.