Help with my build

I am planning to build my first PC. I would like it to be useful for about 4 years, be quiet, and be able to play games such as WoW, Starcraft2, and Diablo 3, when the last two come out. Most of the time it will be used for simple web surfing and office software. I would like to dual boot Windows and Ubuntu Linux, so if anyone knows that I picked something not compatible, please chime in.

I was planning on the following, and would like the opinion of those who know more than me, which I expect is most people on this forum. Please let me know if my components are reasonable for my goals.

Case:
Antec p193 or p183. I'm curious if the side fan is worth it on the 193, or if I should stick with the smaller 183
http://www.newegg.com/Product/Prod [...] 6811129062

Power supply:
Antec CP-850 (850W). If I have the Antec case, may as well get the power supply that is cheaper for it.
http://www.newegg.com/Product/Prod [...] 6817371024

Motherboard:
Asus P5N-D
http://www.newegg.com/Product/Prod [...] 6813131232

CPU:
Intel Core2 Quad Q9400 2.66GHz
http://www.newegg.com/Product/Prod [...] 6819115131

RAM:
Kingston HyperX 4GB DDR2 800
http://www.newegg.com/Product/Prod [...] 6820104020

Hard Drive:
Western Digital Caviar Black 1TB (Is the Green edition too slow to be a primary drive?)
http://www.newegg.com/Product/Prod [...] 6822136284

Monitor:
ASUS VH226H Black 21.5"
http://www.newegg.com/Product/Prod [...] 6824236051

Optical Drive:
LG DVD/CD SATA drive (should I get the IDE version to save my SATA slots for other stuff?)
http://www.newegg.com/Product/Prod [...] 6827136153

Video Card:
ASUS GeForce GTS 250 1GB Dark Kinght
http://www.newegg.com/Product/Prod [...] 6814121309

CPU Cooler:
Noctua NH-C12P (Do I need a CPU cooler that isn't the stock one? Is this significantly more quiet?)
http://www.newegg.com/Product/Prod [...] 6835608001

Thanks in advance for you help, I could really use it.

Steve

I appreciate your advice, but I don't think I fully understand it. What are the differences between those northbridge chipsets that would make me pick one over another?

Also, I don't plan on doing SLI for now, but I might in the future, so I should get a mobo that supports it, right?

In case I do want to SLI in the future, how about this MoBo?
Asuss P5N-T
http://www.newegg.com/Product/Prod [...] 6813131231

Also, I want to go for quiet computing, so I think I'll pick the WD Caviar Blue 640 GB HD since it is suppodely quieter than the 1 TB Caviar Black I had chosen previously.
http://www.newegg.com/Product/Prod [...] 6822136218

Finally, I think the Antec P193 case is too much case for me, and the P183 is better suited:
http://www.newegg.com/Product/Prod [...] 6811129061


I would still like more advice from everyone.

Thanks,
Steve

As it stands, my build is around $1350 from newegg. I could go as high as I need to to meet my goals of:
1) Quiet - my current PC sounds like a jet engine, and it's driving me crazy.
2) Powerful enough for Starcraft2 when it comes out
3) Still be useful in 4 years for medium gaming, not FPS shooters.

So I could spend a few hundred more if I needed to, but I don't want to waste money either.

^ except drop the am3 mobo and ddr3 ram for an am2+ one and ddr2 ram, am3 isn't worth it since it will be obselete in a year anyway.

Nvidia is the better choice I would agree. Since you are set on Nvidia, the Core i7 is your best bet. Nvidia 7xx boards have to many reported problems. I've experienced it myself when my old MSI P7N SLI Platinum fried and took my Q6600 with it.

New Build:
Intel Core i7 920 Nehalem 2.66GHz LGA 1366 130W Quad-Core Processor Model BX80601920 - Retail ($279.99)
http://www.newegg.com/Product/Prod [...] 6819115202

GIGABYTE GA-EX58-UD3R LGA 1366 Intel X58 ATX Intel Motherboard - Retail ($199.99)
http://www.newegg.com/Product/Prod [...] 6813128375

OCZ Platinum 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit Desktop Memory Model OCZ3P1600LV6GK - Retail ($99.99)
http://www.newegg.com/Product/Prod [...] 6820227381

Antec P183 Black Aluminum / Steel / Plastic ATX Mid Tower Computer Case & Antec Signature SG850 850W Continuous Power ATX12V / EPS12V SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Modular ... - Combo Deal ($342.98)
http://www.newegg.com/Product/Comb [...] mbo.194005

Noctua NH-C12P 120mm SSO CPU Cooler - Retail ($64.99)
http://www.newegg.com/Product/Prod [...] 6835608001

ASUS GeForce GTS 250 1GB Dark Kinght ($149.99)
http://www.newegg.com/Product/Prod [...] 6814121309

Western Digital Caviar Black WD6401AALS 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive - OEM ($74.99)
http://www.newegg.com/Product/Prod [...] 6822136319

LG 22X DVD±R DVD Burner with LightScribe Black SATA Model GH22LS30 - OEM ($23.99)
http://www.newegg.com/Product/Prod [...] 6827136153

ASUS VH226H Black 21.5" 2ms(GTG) HDMI Widescreen LCD Monitor - Retail ($179.99)
http://www.newegg.com/Product/Prod [...] 6824236051
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Total Cost: $1,416.90 (Not including Shipping & MIR)
Difference between your original build + $66.90. This price difference is well worth the extra money, IMO.