CPU - I was going to get the FX-6300 but this one went on sale with the RAM stick so I upgraded to the 8320. It's current;y overclocked to 4 GHZ
CPU Cooler - Everywhere said it was a good cooler. It's super quiet but it took me 15 minutes to figure out how to change the prongs to mount it properly.
Mobo - this one was suggested by Lifehacker.com. It works.
RAM - was on sale with the CPU and it had a couple good reviews.
SDD - Samsung good. After mounting it i realized i could mount to the bottom of the case.
HDD- it was on sale.
GPU - the Radeon R9's got good reviews and this one came down to the same price as the R9 270 so I upgraded up to the 270X.
PSU - I realize that I probably should have gotten maybe a 600W PSU but I was trying to stick within a budget (I failed). But it works and it was inexpensive.
O/S - I actually opted for a retail version for $5 more. I just wanted a little piece of mind in case when i installed it I could call Microsoft.