I looked at your list and have a couple questions/suggestions.
Whats your budget? Are you planning on gaming? Is there any specific reason you picked that monitor? you dont really have to answer me just ask yourself cause thay are relavent to the choices and suggestions I made. If you dont game and wont OC then that power will probably be just fine.
First off make sure that the DS3 is rated for a FSB of 1333. Its not listed as such and you may be getting an older rev. You definately want the DS3 rev3.3 that supports fsb of 1333.
If you game you need a better video card. I suggest a X1950XT or better. If money is an issue, suggestions to save money to follow.
Forget the GSkill and get the Crucial Ballistix 2x1GB DDR800 for $85 after rebate. They both use the exact same D9GMH chips. Saves $45
As for the monitor, why not just get an ACER, Hanns-G, or other monitor with the same specs and save yourself a solid $100. With names like Samsung, Pioneer and the other big names your paying extra for the NAME!! I paid $170 for my 19"wide screen Hanns-G six months ago and it has been flawless. Not a single dead or stuck pixel.
Is there a reason you dont want to use the motherboards onboard nic? It works just fine. Save yourself another $22 and skip the 3com nic.
Buy a E6400 to save yourself another $30 if you need to, and just OC. It'll do close to if not over 3.0GHz . Probably will OC just the same as the E6600. If you want to OC you will need to budget for a better then stock heatsink and fan. I use the Scythe ninja for $40. its like $25 cheaper then the ultra high end HS's and you will only run 2-3C hotter for it. But who cares when your laod temp never breaks 50C. Or you can get an Arctic Freezer 7 Pro for about $25 and still keep it inder 60C no problem.
I prefer cases with front AND rear 120mm fans, side fan, and blowhole fan (top of case). That way you get really good airflow THROUGH the case, which is what you want. front fan cools the drives too. Cool air in the front and warm air out the back.
With those simple suggestions you will have just saved yourself about $200. Take $100 and put it into vidoe card and take the other $100 and PUT IT INTO YOUR POWER SUPPLY!!!!
Do not skimp on your power. DO NOT SKIMP ON YOUR POWER!!! I cannot emphasize enough. Nowadays 480W is barely middle of the road and may not be able to handle any serious upgrades or overclocking. AND!!! a cheap PSU can have fatal consequences for your build. I recommend 600W minimum, and 750W is better. A single 12V rail is the best. Yes thats right. 1 single 12V rail is the best way to go for reliable power. But it isnt a must, modular dual and tripple 12V rails are fine as lone as each individual rail has a minimum of 18A and 20-22A or higher per rail is better. Trust me on this I have done more reading then I care to remember on power supplies. As for your originaly asking about a suggestion you need to do your homework and make sure your comfortable with your choice.