z97-pro gamer
i7-4790 ( or k version) or i5-4690k ( cheaper but only 4 threads)
gtx 970
2x 4gb hyperx fury 1866mhz cl10
fsp raider 650watts silver certification
windows 8.1
BENQ GL2460HM 1080p monitor
keyboard+mouse you can buy for 20 pounds in tesco or anywhere cheap.
probably you could do this out of 900 pounds.