Thought & improvements for my First Gaming PC build

Hey, I going for my first gaming PC build. Here's what I've put together. Is this a good build for the budget? Is there anywhere where the build could improve?

MSI GeForce GTX 570 OC Twin FrozR III Power Edition
http://www.overclockers.co.uk/showproduct.php?prodid=GX-129-MS
Intel Core i5-2500K 3.30GHz
http://www.overclockers.co.uk/showproduct.php?prodid=CP-360-IN
Asrock Z68 Extreme4 Gen3
http://www.overclockers.co.uk/showproduct.php?prodid=MB-054-AK
G.Skill RipJawsX 8GB
http://www.overclockers.co.uk/showproduct.php?prodid=MY-060-GS
OCZ ZX Series 850W '80 Plus Gold' Modular Power Supply
http://www.overclockers.co.uk/showproduct.php?prodid=CA-052-OC
Seagate Barracuda Hard Drive
http://www.overclockers.co.uk/showproduct.php?prodid=HD-252-SE
LG CH10LS28 BD-ROM 10x BluRay ROM / DVDRW SATA-II Optical Drive
http://www.overclockers.co.uk/showproduct.php?prodid=CD-114-LG
Corsair Carbide 300R Mid Tower Case
http://www.overclockers.co.uk/showproduct.php?prodid=CA-063-CS

Approximate Purchase Date: April

Budget Range: €1200

System Usage: Gaming

Parts Not Required: keyboard, mouse, monitor, speakers, OS

Preferred Website(s) for Parts: http://www.overclockers.co.uk

Country: Ireland

Overclocking: Yes

SLI or Crossfire: SLI

Monitor Resolution: 1920x1080

Additional Comments: I intend to upgrade the PC in the future with adding another graphics card in SLI, adding more RAM, adding an SSD and another Hard drive.