Advice on builing a PC for a specific type of games?

[-CraZed-]

Here is a build I suggest for around the $1000. It is pretty similar to my Steambox/HTPC setup. It will run Civ5 and Xcom no problem (not to mention just about any other game).

http://pcpartpicker.com/user/CraZed./saved/sdZj4D

There are a few corners I cut like cutting out an overclockable mobo and CPU. I think you could also drop down the GPU to a R9 270X. Also you could go down on the CPU from a 4690 to a 4670 but the price difference is negligible.