Antec's PSU is from the Tier Two and is better than the rest.
Kingston has less RMA value than GSkill or Corsair.
Asus has less RMA value than MSI.
PCPartPicker part list:
http://uk.pcpartpicker.com/p/8bn4f7
Price breakdown by merchant: http://uk.pcpartpicker.com/p/8bn4f7/by_merchant/
CPU: Intel Pentium G3258 3.2GHz Dual-Core Processor (£51.03 @ Amazon UK)
Motherboard: ASRock Z97 Anniversary ATX LGA1150 Motherboard (£56.34 @ Scan.co.uk)
Memory: Kingston HyperX Fury Blue 8GB (2 x 4GB) DDR3-1600 Memory (£34.97 @ Ebuyer)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£34.92 @ Aria PC)
Video Card: Asus GeForce GTX 750 Ti 2GB Video Card (£92.98 @ Amazon UK)
Case: Thermaltake Versa H22 ATX Mid Tower Case (£26.70 @ CCL Computers)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply (£41.28 @ More Computers)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer (£9.36 @ CCL Computers)
Operating System: Microsoft Windows 7 Home Premium SP1 OEM (64-bit) (£67.95 @ Ebuyer)
Monitor: BenQ GL2250HM 60Hz 21.5" Monitor (£89.99 @ Amazon UK)
Total: £505.52
Prices include shipping, taxes, and discounts when available