Looks like you got some advice from the thread I started which is good because I can give you my experience with most of what you have picked.
The cool master case worked great, plenty of space to work. And always a plus no tools required (it does come with screws for optical and HDD if you still want to use them)
I would suggest getting SATA connectors with right angles
this will make installation of optical drives much easier
The DFI mobo works great, the only problem is if you decide to get a bigger cpu heat sink like the Core-Contact Freezer it will hit the north bridge heat sink. I looked at some videos of the Xigmatex and its bracket system is a lot smaller so you should have no problems with that.
Because your a gamer you could go with the E8500 cpu, for the price difference though, I think the E8400 is fine.
I only have a single 4850 gpu right now and I can run Bioshock, and world in conflict on full settings without a problem, so having two CF will give you a good amount to play with.
I only see two potential problems.
First: Be careful with running CF. You said that you where software based so hopefully you wont have a problem working with this. CF will only work if you program is running in a Fullscreen mode. The problem with certain games is that they will run in a Fake Full Screen mode. Usually if they do there is a line of code in the config files that resembles FakeFullScreen = 1; (This code varies for different software.) Just do a little research on the games you play and there compatibility with CF.
Second concern is be careful of power consumption. No matter how great of a system you build if you have power problems it will run like crap. The the gpu’s crossfired will run at around 300W without overclocking. CPU 65W w/o OC. Then when you include HDD, optical, fans, cpu cooler, ram, and mobo peripherals you probably around 450W. This is without OC and this is generalized best guess. Personally I would rather be safe the sorry so maybe consider 550 or 600W PSU.