Are these parts compatible for a good gaming PC?

Solution
500 pounds budget rig and the case costs more than the motherboard.

CPU: AMD FX-6300 3.5GHz 6-Core Processor (£74.34 @ Aria PC)
Motherboard: Asus M5A97 R2.0 ATX AM3+ Motherboard (£61.92 @ Ebuyer)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-2133 Memory (£58.67 @ Ebuyer)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£39.99 @ Amazon UK)
Video Card: MSI Radeon R9 280X 3GB TWIN FROZR Video Card (£177.94 @ Scan.co.uk)
Case: NZXT Source 210 (Black) ATX Mid Tower Case (£30.25 @ Scan.co.uk)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (£62.78 @ CCL Computers)...
500 pounds budget rig and the case costs more than the motherboard.

CPU: AMD FX-6300 3.5GHz 6-Core Processor (£74.34 @ Aria PC)
Motherboard: Asus M5A97 R2.0 ATX AM3+ Motherboard (£61.92 @ Ebuyer)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-2133 Memory (£58.67 @ Ebuyer)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£39.99 @ Amazon UK)
Video Card: MSI Radeon R9 280X 3GB TWIN FROZR Video Card (£177.94 @ Scan.co.uk)
Case: NZXT Source 210 (Black) ATX Mid Tower Case (£30.25 @ Scan.co.uk)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (£62.78 @ CCL Computers)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer (£10.46 @ Aria PC)
Total: £516.35

You are welcome, but if thats too much :

CPU: AMD FX-6300 3.5GHz 6-Core Processor (£74.34 @ Aria PC)
Motherboard: Asus M5A97 R2.0 ATX AM3+ Motherboard (£61.92 @ Ebuyer)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-2133 Memory (£58.67 @ Ebuyer)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£39.99 @ Amazon UK)
Video Card: Gigabyte Radeon R9 280 3GB WINDFORCE Video Card (£141.99 @ Ebuyer)
Case: NZXT Source 210 (Black) ATX Mid Tower Case (£30.25 @ Scan.co.uk)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (£62.78 @ CCL Computers)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer (£10.46 @ Aria PC)
Total: £480.40

or :

CPU: AMD FX-6300 3.5GHz 6-Core Processor (£74.34 @ Aria PC)
Motherboard: Asus M5A97 R2.0 ATX AM3+ Motherboard (£61.92 @ Ebuyer)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-2133 Memory (£58.67 @ Ebuyer)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£39.99 @ Amazon UK)
Video Card: Sapphire Radeon R9 270X 2GB Dual-X Video Card (£129.95 @ Amazon UK)
Case: NZXT Source 210 (Black) ATX Mid Tower Case (£30.25 @ Scan.co.uk)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (£62.78 @ CCL Computers)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer (£10.46 @ Aria PC)
Total: £468.36
 
Solution