Be sure to keep us posted with what parts you go with!

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Includes a 4k panel, so it's a little over budget, but this rig is perfectly 4k capable. The R9 Nano is about £100 more than the GTX 970, but performs closer to the GTX 980Ti. The performance you get for the price, is ridiculous. XFire support, so you can easily add a 2nd Nano at any point. Nice big SSD for your OS, and some games/programs, then the HDD for the rest of your storage.

If you can't go over budget, or if you don't want 4k, you could get this 1440p panel instead;
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The Nano would slay at 1440p. With the 1440p panel, you can afford a nice 960GB/1TB SSD instead, or a 240/256GB SSD and a 256GB 950 PRO.

Since it appears you're mostly gaming, with maybe a little editing, the 6700k would be a better choice than the 5820k.