I would drop the 1tb for a 640 black, itll be a decent amount faster then the green drive. Also just a heads up but the precision PC gaming headset is hella uncomfortable, if you watch Futureshop they normally have their higher end plantronics on for cheap, I recently got the audio .370s for $24 and their pretty comfortable and offer decent sound quality.
Also id get this over the MX518,
Steelseries Ikari Optical Professional Gaming Mouse - DirectCanada Steelseries 3H Foldable Gaming Stereo Headset W/ Microphone - DirectCanada would probubly offer better sound quality and comfort over the logitechs.
Rest of the build looks good, personally id take a CM 690 over the 900 case, but since you have a modular PSU cable management should be to much of an issue in the 900.
Oh and personally id drop the 9800GTX+ for this ....
BFG GeForce GTX 260 OC MAXCORE55 590MHZ 896MB 1.998GHZ GDDR3 PCI-E Dual DVI-I Video Card - DirectCanada
Trust me, I went from a 9800GTX+, then 9800GTX sli, to the GTX 260 core 216 and the change was VERY noticable, I get awesome frame rates on crysis at gamer settings in DX10 and any other game is well over 60 FPS at maxed settings.
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The Builders Hammer
Asrock P67 Fatal1ty, Intel i5 2500K @ 5.1ghz, 16gb HyperX 1600 CL8, Evga GTX 580 SC SLIed and water-cooled, HX850, Crucial M4 64gb, 640 black, 1tb + 3x 2tb greens, Haf X.
BF BC2: Bishop_SHIFT, Steam: Realityshift84, Xbox Live - SHIFTEDone84 ... Come play.