Checking back...
Oh I 100% agree with BaldMan's opinion! (scrap XP for Windows 7). With the OS being free for almost a year, it will save you $$ for this purchase and delay the OS cost. And you can put that $$ into other aspects of your hardware purchase.
BTW, recently there have been advertisements for low cost upgrades to Windows 7. A local store in my area was offering the "home premium" upgrade version of Windows 7 for $40....and the "professional" upgrade version (similar to Vista Business...and the older XP Pro) for $90. The only negative was that you have to go into the store to obtain a coupon. When Windows 7 is finally released, you will go back into the store (with your coupon) and then purchase the software.
Micro Center offering Windows 7 coupons for $39 and $89
One other note....
From the advise of others, I've recently purchased the Freezer 7 CPU fan you are looking at. Here in the US, it was recently onsale for $27 with free shipping.
Newegg.com - ARCTIC COOLING Freezer 7 Pro 92mm CPU Cooler - CPU Fans & Heatsinks
There are a LOT of positive reviews on for that product and I think you are making an excellent choice with the Freezer 7 for your CPU fan! Great Job!
Lastly about your RAM decision.
I spent almost 2 weeks trying to decide on which RAM was best for the GA-EP45-UD3R. I narrowed it down to 2 options:
G.Skill F2-8500CL5D-4GBPK
Newegg.com - G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model F2-8500CL5D-4GBPK - Desktop Memory
Kingston KHX8500D2K2/4G
Newegg.com - Kingston HyperX 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 Desktop Memory Model KHX8500D2K2/4G - Desktop Memory
The Kingston RAM is on Gigabyte's Recommended Memory list...the G.Skill is not. However, the G.Skill memory is widely used and has a very high positive approval.
Ultimately I went with the advise of others here and purchased the G.Skill. I'm not sure if its available with you reside, but here in the US, it is a good price in comparison to others.
Let us know which components you purchase and how your build goes! Best wishes on your build.