2U Rackmount Gaming Server

Approximate Purchase Date: Month or two.

Budget Range: $1,500 - $2,000 (AUS)

System Usage: Will be used for a colocation dedicated gaming server.

Parts I have chosen -

Case - Supermicro 825TQ-700LPB Rackmount Server Chassis - 700W PSU - 2U

Motherboard - ASUS P8Z77-V Motherboard : LGA1155, Z77, 4xDDR3-1333, 2xPCI-Ex16 v2.0, 2xPCI-Ex16 v3.0, 2xSATA-III, 4xSATA-II, RAID, 1xGigLAN, 8Chl-HD, USB3.0, VGA, DVI, HDMI, ATX

CPU - Intel Core i5 2500K Quad Core CPU (3.30GHz - 3.70GHz Turbo, 850-1100MHz GPU) - LGA1155, 1333MHz, 5.0 GT/s DMI, 6MB Cache, 32nm, 95W

CPU FAN - Intel BXSTS200C - Thermal Solution - (Active Heat Sink with Removable Fan) - For LGA2011 Serverboards

RAM - G.Skill 8GB (2 x 4GB) PC3-14900 1866MHz DDR3 RAM - 8-9-8-24 - Ripjaws-X - X2

O/S HDD - Got stuck here, usually have RAID for data servers but this one will be purely for game renting, I was thinking a smaller SSD hard disk drive for the O/S?

SERVER HDD - and a Larger SSD hard disk drive for the game server files?

Additional Comments:
My limitations are the 2U case at it will be going into a 2U colocation rack.
The server will only be used for renting for dedicated gaming servers. TF2, BF3, Natural Selection 2: This will be the main game to be run from it, it's a bit of a beast at chewing servers up and currently stats showing that the i5 2500k is the best type of server for this game, and I don't need ECC.
I will be trying to overclock, but not sure how that will go yet, depending on location in rackmount, power usage, etc...
Hard drives I was either thinking the above I have written or just RAIDing some SATA 7200rpm HDDs, it doesn't need huge amounts of space, it will not be for holding data.

Thank you for taking the time to read my thread.
Any advice would be much appreciated.

Cheers.