High-end homebuild setup (yet to build)

[ChrisTheChip]

Hi there everyone, I'm new to Tom's Hardware but let's dive into the deep end. I've been doing some extensive research into an affordable high-end gaming pc that comes to around £1000 with all peripherals + monitor included. Here's the specs, have a look and let me know what you think and if there's anything you would personally change:
Note: The components in italics have already been bought as they were either on offer or were low in stock.

Case - NZXT Lexa S Case USB3.0 Version
Motherboard - Gigabyte GA-Z77X-D3H Socket 1155 VGA DVI HDMI 8 Channel Audio ATX Motherboard
Processor - Intel Core i5 3570 3.40GHz Socket 1155 6MB L3 Cache Retail Boxed Processor
Heatsink - Arctic Cooling Freezer 7 Pro rev 2 Socket 775, 1156, 1155, 1366, AM2, AM3 Heatpipe CPU Cooler
Extra Fan - Antec TrueQuiet 140mm Case Fan
RAM - Corsair 8GB DDR3 1600MHz Vengeance Memory (blue)
Video Card - Sapphire HD 7870 FleX GHZ Edition 2GB GDDR5 Dual DVI HDMI DisplayPort PCI-E Graphics Card
Optical Drive - Samsung SH-S222BB SATA DVD Drive | Retail
Hard-Disk Drive - Seagate 2TB Barracuda Internal Hard Drive
Solid-State Drive - OCZ 60GB Agility 3 SSD
Power Supply Unit - Corsair TX 650W PSU - 80plus Bronze Certified
Wireless Card - TP-Link 300mbps Wireless N Pci Express Adapter

Keyboard - Microsoft SideWinder X4 Gaming Keyboard
Mouse - Sharkoon Drakonia Laser Mouse
Mouse Mat - Sharkoon Drakonia Gaming Mat
Monitor - LG IPS234V-PN 23" LED LCD HDMI IPS Monitor
Speakers - Logitech X-140 Black 2.0 Speakers - 5W RMS

I look forward to hearing some constructive feedback and potential improvements!

 

[ChrisTheChip]

Also, I'd like to get a modular PSU instead of the non-modular one listed. However, all of the modular corsair PSUs have 8-pin CPU power instead of the required 4-pin ATX compliance for the motherboard. Is it possible to just use half of the input and leave the other half hanging over?