A Mac User's First PC Build - Looking for feedback

I'd switch the GPU for a GTX 960. Reason being that in my experience the nvidia drivers are more stable than the AMD ones and nvidia seems to have less compatibility issues across the board. Also it is rated slightly better in performance, but it's on you to decide if this justifies the 20-30 bucks more. Again, this is only my opinion based on my experience. Your mileage may vary.

Other than that, it seems you have a decent gaming build there. Welcome to the PC DIY community!

It's a good build, at a good price point OP, just consider dropping in an SSD, it'll help a ton.
And I would also stick with the R9 280 instead of the 270, or even go with a 290, which doesn't cost much more.

Great suggestions. How about this (AMD) configuration:

Mobo: MSI ATX DDR3 2133 Motherboard 970 GAMING
CPU: AMD FD8320FRHKBOX FX-8320 FX-Series 8-Core Black Edition
GPU: Sapphire Radeon R9 280 3GB GDDR5 DVI-I/DVI-D/HDMI/DP Dual-X with PCI-Express Graphics Card Boost 11230-00-20G
RAM: Kingston HyperX FURY 8GB Kit (2x4GB) 1600MHz DDR3 CL10 DIMM - Black*
Storage: WD Blue 1TB SATA 6Gb/s 7200rpm Internal Hard Drive
PSU: EVGA SuperNOVA 650G1 650W ATX12V Power Supply 120-G1-0650-XR
Case: Corsair Carbide Series 300R

* another 4gb kit would be my first upgrade, bumping system to 16gb

Two questions:
- Would this get me 1920x1080 gaming at high settings for most modern titles?
- If I run this 'as-is', do I need cooling for now? Seems like I can add it later if I want to overclock anything

Thanks again, guys.