Based on Scott's recomendation I had a good look at Scan and I have added a 3XS SI77 PowerDAW with the configuration below to the shortlist.
As long as I can find space I will probably drop the dual boot idea and retain my old DAW for "office" use and use something like a Belkin OmniView USB Soho Series 2-Port DVI KVM Switch so I can share keyboard, mouse and screens between the two computers.
I still have a couple of questions.
Is the 750GB Seagate ST750LX003 MomentusXT Hybrid Solid State system drive a good option or would I be better with a conventional Western Digital Cavier Black, possibly with a cache SSD drive?
Is the 520 watt power supply OK or should I go for the 650W be quiet! Dark Power Pro 10 BN201 option?

System overview
System Overview Custom Coloured Cases: *No Custom Colour Required*
Case: Nanoxia Deep Silence One Anthracite Ultimate Low Noise PC Case USB 3.0
CPU: Intel Core i7 3770K
Overclocking - CPU: Intel® Core™ Ivy Bridge CPU professionally overclocked by our 3XS engineers to 4.4Ghz
CPU Coolers: Prolimatech Armageddon Ultra High End CPU Cooler 6 Heat Pipe Intel Socket LGA 775 1366 1156 1155
Memory: 32GB (4x8GB) Corsair DDR3 Vengeance 1600Mhz
Power Supply Unit: 520W Seasonic M12II-520 87% Efficiency
NVIDIA Graphics: 1GB Asus GT 610 Silent PCIe 2.0 (x16) 40nm 1200MHz GDDR3 GPU 810MHz 48 Cores LP Passive
System Drives - SSD or Mechanical: 750GB Seagate ST750LX003 MomentusXT Hybrid Solid State 2.5" SATA 6Gb s 7200rpm 32MB Cache
Storage Hard drives: 2TB Seagate ST2000DM001 Barracuda 7200.14 SATA 3 6GB s 7200rpm 64MB Cache , 2 selected
Solid State Drives - Data: 240GB Corsair Force 3 Read 550MB s Write 520MB s SF-2281
Solid State Drive - SRT SSD Cache Drive.: *Cache SSD Drive Not Required*
Optical Drive 1 - DVD Blu Ray: Samsung SH-224BB - 24X DVD Writer