Custom gaming pc review please..

At that resolution you should check out the 6950 1GB if you don't plan to overclock. As for if you plan to overclock the 560 ti would be a smart choice.

What's your budget not inlcuding monitor?

If it's 1K, check out my build in my siggy. That'll work out just nicely.

First, what is your budget on the graphics card so that we can tell you what to get and how much power you will need?
AND stick to AMD/ATI because your mobo is Crossfire not SLI.

AND your CPU won't bottleneck any of these cards-

The absolute BEST you can get FOR:

For $360 you can get TWO 6850s in Crossfire for $180 each. (What I recommend)

For $275 you can get ONE 6950.

For $250 you can get ONE 6870.

For $180 you can get ONE 6850.

For $130 you can get ONE 5770.

These are the best graphics cards for the money according to Tom's Hardware and ME as well as some other sites.

For a Case, I think you should take a look at the NZXT Tempest EVO, you may like it, it's my favorite sub $100 mid tower. If you don't like the EVO, the Antec 900 has better air flow to all components however the Storm Scout looks better in my opinion, it's also black on the inside, in addition the Scout cools your graphics card better.

About the hard drives, if you install games on an external hard drive, they can still only be played on the computer you installed them on, and they would perform bad and load SLOW because external hard drives use the USB interface which is nothing compared to the internal SATA interface, even USB 3.0 is too slow.

A SSD drive is too expensive and costs $120 for 60GB so I think you should just get a 1TB Caviar Black with Sata 6-Gbps and 64MB cache, a SSD drive won't improve game performance, it will only improve loading times and searching through files, copying, and OS boot times,

It's not worth the money because you can spend that money on a good graphics card, every thing else is good but you should really get an aftermarket CPU cooler for overclocking, the Hyper 212+ is the best cheap one, it only costs $30, with that you can over clock your CPU to over 4Ghz if you have air conditioning, if not 3.6-3.8 is possible.

How set are you on that CPU? The 6-cores won't really provide a performance boost over the phenom II 4 core CPUs like the 955/65/70. I'd recommend getting a phenom 955 and just OC the puppy up. This way you can spend a bit more cash on the video card and still have the same performance for gaming.

http://www.antec.outervision.com/ provides a rough guesstimate as to how many watts your rig will consume.