CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor (£164.99 @ Aria PC)
CPU Cooler: Phanteks PH-TC14PE 78.1 CFM CPU Cooler (£75.23 @ Amazon UK)
Motherboard: Gigabyte GA-Z77X-UP4 TH ATX LGA1155 Motherboard (£151.01 @ Aria PC)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory (£53.97 @ Dabs)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£47.94 @ CCL Computers)
Video Card: MSI GeForce GTX 780 3GB Video Card (£550.97 @ Dabs)
Case: Corsair 600T White Graphite ATX Mid Tower Case (£143.27 @ Aria PC)
Power Supply: Corsair Builder 600W 80 PLUS Certified ATX12V Power Supply (£53.46 @ Aria PC)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer (£11.79 @ Amazon UK)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£65.99 @ Aria PC)
Monitor: Asus VG248QE 144Hz 24.0" Monitor (£274.97 @ Amazon UK)
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-05-26 16:56 BST+0100)
You've still got plenty of wiggle room in your budget I see. I would go with a newer Haswell processor (i.e. 4670k and an 1150 MOBO, probably asus Z87 PRO) and I would add a SSD like a 128GB Samsung 840 pro for a boot drive. Also Try and go with an 800W PSU as 600 will not be enough to SLI 780s in the future. Try a corsair HX series. That should bring you to around 1800!
EDIT: your post title says 2000 but in your post it says 1500...which is it?