It really depends on what you are planning for your games. You have a budget for £2000, but I assume you don't want to spend that much for the sake of it. But regardless, I cannot stress enough how much of a waste going i7 980x would be. It is an overpriced pile of crap compared to te Sandy Bridge tech especially for gaming, DO NOT pay good money for it - even if sold at the same price as the new chips I would not pay for it
Me personally, I would be looking at:
i7 2600k - £263
http://www.scan.co.uk/products/intel-core-i7-2600k-unlocked-socket-1155-sandy-bridge-quad-core-34-ghz-8mb-cache-95w-retail
(though personally for gaming I think anymore than i5 2500k is excessive)
CPU Asus Sabertooth - £173
http://www.scan.co.uk/products/asus-sabertooth-p67-intel-p67-express-s-1155-pci-e-20-ddr3-1866-sata-6gb-s-sata-raid-atx
HAF X - £129
http://www.scan.co.uk/products/coolermaster-haf-x-black-full-gaming-tower-case-inc-side-window-usb3-w-o-psu
(though again it is personal preference, hell, I think the 912+ gives all most need at £57)
HDD - Samsung Spinpoint F3 1tb - £41
http://www.scan.co.uk/products/ss1tb-samsung-hd103sj-spinpoint-f3-sata-3gb-s-7200rpm-32mb-cache-89-ms-ncq-oem
RAM - Corsair 1600mhz 8gb - £83
http://www.scan.co.uk/products/8gb-(4x2gb)-corsair-xms3-classic-ddr3-pc3-12800-(1600)-non-ecc-unbuffered-cas-9-9-9-24-xmp-165v
PSU - XFX Black Edition 850W- £114
http://www.scan.co.uk/products/850w-xfx-black-edition-modular-80-plus-silver-88-eff-sli-crossfire-eps-12v-135mm-quiet-fan
GPU - GTX 570 - £285
http://www.scan.co.uk/products/1280mb-palit-gtx-570-sonic-40nm-3900mhz-gddr5-gpu-750mhz-shader-1500mhz-480-cores-dp-hdmi
Cooler ~ anywhere from £20 - £50. My personal preference is the Hyper 212+ with an additional fan attached.
SSD if you want one and as you have the budget for it you may aswell. Probably don't really need more than 120gb, 64gb would possibly do.
Windows 7 - £75
24 inch monitor - £170 (lots to choose from)
I would not go with an i7 980x at all. The new Sandy Bridge is a far better chip and a far kinder price. There are issues with motherboards atm, but you can either wait, or just buy it and hope not to be effected.
I am unsure how severe the issue is, sata is backwards compatible, so, if you connect to the 6gb/s sata slots will it be effected by the issue the 3gb/s sffer from? I don't know but if not then there is no issue with buying now. If there is an issue then you need to wait because going back to i7 980x is a waste - the Sandy Bridges out perform it.
As gaming is your main function, then you should not really need more than a 1tb drive plus an SSD (the SSD is for OS and games you regularly play. It is indulgent but if you can afford one it is a nice to have) hell, I don't even fill a 500gb drive with my games and music.
As far as I am concerned £800 is all you need for a great gaming machine (+cash for Windows and monitor) About £950 if you want to indulge in the items in brackets which for me personally are not required
i5 2500k
Asus P8P67 Pro (or Sabrtooth if you want 16/16 SLI)
Hyper212+
Corsair RAM 4gb (can go for 8 if you wish)
GTX 570
500gb Samsung Spinpoint F3 (or 1Tb if you wish)
HAF 912+ case (922 or bigger if you wish)
DVD Drive - any £13 drive
That should give all the power you need for gaming for a good while, with the option of adding a second card