What computer should I choose?

Objective of the computer:
- Play games such as World of Warcraft, DayZ, GMod, Minecraft, and so on (not too heavy, I suppose).
- Photoshop/Flash/After Effects projects (I have 8 gigs of RAM and currently After Effects alone wastes me 4 gigs of RAM alone)
- Game Development (using cry engine 3/unreal engine 4/autodesk, etc)

Which is the best?

LENOVO Z50 £699
Intel® Core™ i7-4510U Processor
- Dual-core
- 2 GHz / 3.1 GHz with Turbo Boost
- 4 MB cache
Memory: 16 GB
Graphics: NVIDIA GeForce 840M
Hard drive: 1 TB SSHD

OR

HP ENVY 17-k251na for £799
Intel® Core™ i7-5500U Processor
- Dual-core
- 2.4 GHz
- 4 MB cache
Memory: 12 GB
Graphics: NVIDIA® GeForce® GTX 850M
Hard drive: 1 TB & 8 GB SSD

OR

LENOVO Y50 £899
Intel® Core™ i7-4710HQ Processor
- Quad-core
- 2.5 GHz / 3.5 GHz with TurboBoost
- 6 MB cache
Memory: 16 GB
Graphics: NVIDIA® GeForce® GTX 860M
Hard drive: 1 TB SSHD

My personal comment: I have never used Lenovo, but I have tried an HP Pavilion and it broke right away when it fell on the floor for the first time (screen frame fell off etc!) from a really small distance (about 20/30cm). I'm looking for full performance. The Lenovo looks great but I'm not sure about the graphics card, because I know GTX is better than GT and GT is better than just GeForce, right?
I realize the third lenovo is the best in performance, but the price is kind of worrying, so I'm asking for an opinion on that too.

So, which one should I choose?
Thanks.

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