Using my discounts ( I own a small retail operation) here's what I was able to come up with for £350
£95.65 AMD FX-8350 with closed loop cooler
£38.97 Coolmax ZPG-600B 80 Gold PSU
£45.67 ASUS M5A99X EVO R2.0
£37.68 Gskill Sniper Series 8 GB (2x4GB sticks)DDR3 @ 1866
£42.73 PNY XLRB 240GB SSD
£81.37 Power Cooler AX7870(Radeon 7870)
£4.50 used Xbox 360 wired controller
£0.99 LG BDXL blu-ray burner (I actually have 25 of these in stock at the moment so I am giving myself the employee discount
)
£0.00 Raidmax Raptor Case ( my supplier has a ton of these and has given me about 6 of them for custom rigs in the past and shows no signs of letting up)
£0.00 Windows 7 OEM enterprise edition install
£0.00 Generic Keyboard and Mouse
Grand total of £347.66
I could probably do better but I think this is sufficient to kick the Xbox One to the curb.