First let me say what a god awful site that is, also whoever came up with the bundles needs bludgeoning with a Victorian table leg, an I7 with a 75 (non Ti!) and only TWO 270x bundles!
I've come round to the fact the 860k isn't as god awful as I thought, it many games it's ok as the GPU is the limiting factor, however it holds back the GPU in some certain games, GTA 5 is one of them (from what I saw), it just won't reach 60fps steadily, although you'll still get 30fps if you lock it.
This one is a 860k 260x for £450 all you need is the OS, the 260x is slightly better than the 750(non Ti) and as good as a 750Ti, your looking at Medium 1080p graphics, good value for money but hey you might as well spend your voucher right?
http://www.game.co.uk/en/fierce-venus-quad-core-gaming-pc-bundle-athlon-x4-860k-4-3ghz-r7-260x-2gb-8gb-wifi-619710?pageSize=40&catGroupId=&vendorShopId=2046
The 8 Core FX 8350 with the 750Ti bundle, as good as a 260X, in the future with DX12 games are able to make better use of all the cores available so it may be possible that these 8 core processors will be excellent gamers in the future, however I would air on the side of caution, just because they're able to doesn't mean they will. I've watched a few benchmarks of GTA 5 with this CPU and a 270X and a and it definitely suffers because of it compared to my i5 and 270X. At around £630-£650 once you've added and OS and monitor etc. I wouldn't recommend it on value. I never saw any 6 core CPUs there.
860k with GTX 960, £520, needs OS. on games where you aren't limited by the CPU, you'll have gorgeous high maybe ultra settings.
http://www.game.co.uk/en/fierce-mars-quad-core-gaming-pc-bundle-athlon-x4-860k-4-3ghz-gtx-960-2gb-8gb-wifi-620258?pageSize=40&catGroupId=&vendorShopId=2046
i5 with GTX 960 £600 Needs OS and monitor, keyboard and mouse, you'd need about £730-£750 to get this up and running, CPU won't hold you back on anything really. High/ultra 1080p graphics and 60fps.
http://www.game.co.uk/en/fierce-stheno-quadcore-gaming-pc-intel-core-i5-4690-3-5ghz-cpu-gtx-960-2gb-graphics-8gb-ram-1tb-327118?pageNumber=5&pageSize=40&catGroupId=&vendorShopId=2046
I looked at EVERY ONE they had and the two I'd recommend are the i5 GTX 960 or the 860k GTX 960.
I've been watching many benchmarks with the 860k and it'll play modern games like GTA 5, Witcher 3 and Project CARS at 30fps+ (I'd lock it there for a smoother experience) So if you don't mind sometimes having to reduce the FPS count then you should be happy with the 860k.
Of course if it was possible then get the i5 GTX 960 but I know it may not be an option and I wouldn't like you to feel forced to go out of your comfort zone to appease a bunch of geeks on the internet
😉
Side Rant: GAME have a god awful selection of PC's
😛 350 PC's and only 3 have an i5!
Edit: JUST seen your most recent post, if they can upgrade parts then ask them how much for an i5 and 270X
Don't worry about getting a k version too much, unless it comes pre overclocked you'd only risk voiding your warranty.
That PSU is a bit poor but to be honest if they cover your PC for 2 years leave it there. They'll be the one paying for replacements.
Stay away from the G2020, I'm shocked to see it there, it's out of production and it's crap for gaming, I've had one!. Worst of the lot