Getting a gaming rig. Buy or Build?

[youarebadatgames]

If you haven't already you should check out Anandtech's system buyer's guides for starters, they usually do pretty well on bang for your buck.

http://www.anandtech.com/guides/showdoc.aspx?i=3610

Edit: It's a little out of date though, you can probably do better getting the newer equivalents.