Everything looks okay, except for the power supply. I don't think 430W will be able to run a 7850.
You motherboard is fine, you don't need an ATX motherboard unless you want to either crossfire or overclock, which I highly doubt at your price point. You don't need to worry about your case looking empty anyways, you don't have a case with a window. If anything, the smaller motherboard will slightly improve airflow.
I'd recommend this RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16820148544&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=
It's cheaper and for the most part has the same specifications. If you're not overclocking your RAM, you don't really need a heat spreader.
Try this optical drive and save a dollar and also get a better brand: http://www.newegg.com/Product/Product.aspx?Item=N82E16827135204&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=
Consider this power supply:
http://www.amazon.com/dp/B004IZN3K2/?tag=pcpapi-20
It's a better power supply than the Corsair, and the main difference aside from the 20W difference, is that this power supply is more efficient and at max load can pull 100W more than listed. At full load it can pull 550W at an astonishing 81% efficiency (really good for the price point) and at 450W it retains 85% efficiency. It will run your card better than the CX 430, and is more efficient.
Other than that, you build looks fine