Here is what I would do if you don't ever use rebates, but are willing to go with promo codes:
Case & PSU:
Cooler Master Elite 350 w/ 500W PSU $68 including shipping
Processor:
AMD FX-6300 $100 (with coupon code)
MoBo:
MSI 970 Gaming AM3+ AMD 970 SATA 6Gb/s USB 3.0 ATX AMD Motherboard $90
GPU & Ram Combo:
R9 270 & 2x4gb @ 1600mhz & 9 cas $235
HDD:
WD Blue 1TB $60
Total -
$553
Pros: by far the best bang for the buck. FX-6300 and R9 270 are amazing value right now, and hitting these CPU/GPU can be huge. The mobo may be a bit more than you need, but it's still fairly cheap. The real risk is of a faulty PSU. Normally I would stay away from any PSU included with a case, but Cooler Master is a well known brand and makes some great PSUs. Again, this PSU may be the downfall of the build, and if you were willing to spend another $50 you could get a different case and a different PSU (Rosewill Challenger and a Corsair CX-500 would be my recommendations, and that's DEFINITELY where I would put the other $50), but if you insist on staying right near $550, this is the best I could do. Risky, especially considering newegg doesn't list the full PSU specs and there's a chance it might not even come with the connector you need, and another chance it just isn't up to snuff. However if you want an R9 270 and an FX-6300, it's the only way I could think of doing it without gimping you with 4GB of ram.
@RazerZ: Your build is impossible for that price point. You're using old coupon codes multiple times (VCO doesn't work anymore and there's a $20 savings cap, yet you use it for way more than $20). Otherwise your build is definitely the best bang for the buck.