For $1200-1500 you can build something that will play all your games well and will easily handle AH. For $3000 you can be on the bleeding edge of technology. So as far as builds go you're saying that money isn't an object.
I built mine for about $2000 but that included a monitor, mouse, keyboad, speakers, power strips, cables, etc., etc., etc. as I kept my old machine and mostly built based on bang for the buck. I run AH at 60 fps (monitor refresh rate) steady.
I'm not saying don't spend the money because you can build a really nice machine but want you to realize that you don't need to in the world of builds like you might buying pre-built.