Will this gaming rig work? Also, are some of the parts unecessary?

[THE_WRAITH]

Hello everyone, before I start I'd just like to apologise for the length of this post, I've been looking through these forums for a couple months now while researching for parts. I have experience in modifying PCs (changing parts in pre-built PCs), this will be my first full build. I've now made an account on the basis of getting advice. I'm a student with a budget of £600, I can stretch to a bit more and I've made this plan up:

Motherboard (Already bought):
http://www.amazon.co.uk/Asus-Motherboard-CrossFireX-Intelligent-Processors/dp/B007KZQE7Q/ref=pd_sim_computers_1

RAM:
http://www.amazon.co.uk/Corsair-CMZ8GX3M2A1600C9-1600MHz-Vengeance-Memory/dp/B004CRSM4I/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=IHOGHCSEW4M9F

CPU:
http://www.amazon.co.uk/Intel-Generation-i5-3550-3-3GHz-Technology/dp/B007RUZJCK/ref=wl_it_dp_o_pdT1_nS_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I2870JLLIL41UP

PSU:
http://www.amazon.co.uk/Corsair-CX750-Builder-Series-Bronze/dp/B008RJZR40/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I2SYGW7UF594RU

Case:
http://www.amazon.co.uk/Coolermaster-Storm-Enforcer-Tower-Case/dp/B004S9S218/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I351UFUXBFF3MG

HDD:
http://www.amazon.co.uk/Western-Digital-Caviar-SATAIII-Internal/dp/B00461G3MS/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I1F3AYTOB0UQ5A

GPU:
http://www.amazon.co.uk/Sapphire-11200-07-20G-Graphics-HD7850-GDDR5/dp/B008HV63NM/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I21QP20M67E5OA

OR

http://www.amazon.co.uk/Sapphire-11199-00-20G-HD7870-GDDR5-Graphics/dp/B007MUJL2E/ref=sr_1_1?ie=UTF8&qid=1354813008&sr=8-1

Wi-Fi Card (Temporary, cannot use Ethernet due to where my PC will be stationed for a few months):
http://www.amazon.co.uk/TL-WN881ND-300Mbps-Wireless-Express-Adapter/dp/B006BSPTAQ/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I3RP9VSO27PWNG

I will be using a 1920 x 1080p screen (a 24" monitor and a 42" LCD TV) and wish to reach 40fps or more on Ultra settings for most games and run dolphin emulator. I am not interested in dual monitoring, overclocking or cross fire. My questions are:
1. Will this rig work?
2. Which GPU should I go for, 7870 or 7850? Is the difference worth getting the 7870 over the 7850?
3. Is the PSU too big?
4. Any advice on cutting costs? I do want a good case in mind.

I'm open to any suggestions to change the setup (except for AMD CPUs). Thank you so much in advance to anyone who helps

 

[THE_WRAITH]

Almost forgot, I need a good headset, I've seen this:
http://www.amazon.co.uk/Plantronics-86050-05-Gamecom-Gaming-Headset/dp/B0079G2Y2A/ref=wl_it_dp_o_pdT1_nS_nC?ie=UTF8&colid=CITB4T8TLFG6&coliid=I113UQGV0Z8EPV

I don't want to spend too much over £20, something decent that's comfy with a good mic and sound would be great. Thanks again.

 

[hugh117]

PSU is overkill, you'll be fine with a 600w

 

[THE_WRAITH]

PSU is overkill, you'll be fine with a 600w

Thank you! Had a conversation with a friend who has a similar setup to this (except he went with AMD FX4100.......) who said his required a 750w PSU, so I was unsure :S