... but don't blame me
Case already has front, rear and side fans. Looks ok.
Processor. Looks like hey are building this for you? You could go overclocked but you'd need to be sure the cooler can support that (if they are buildng it they should advise and guarantee it)
Cooler - presumably up to the job, ask them.
Extra Case fan - can always add later if required.
Video card - you have checked the 1.5Gb not the 3Gb
Drives look ok dependong on how many flight sims you intend to fit on the SSD. HDD for the other junk.
Power supply. Looks healthy but ask them if they are building it. Can find some websites where you plug in all the kit and it tells you the PSU requirement.
Wireless networking - None. My preference is hard wired for gaming but if you do go wireless get the n band router not the g band (802.11
n)
Windows 7 Home Premium should be fine, I have that and no problems with CoD. XP seems to have trouble running CoD for many people and I would move on anyway.
EDIT: Other suppliers? try
www.scan.co.uk. They build some impressive systems, I have bought from them for years. They built my 3XS system and were very supportive when I ran into a Motherboard X58 chipset/SSD problem.