The X4 940 can only use DDR2! I would change the Ebuyer build back to the X4 925 which can use DDR3. Also the X4 925 uses less power too!
If you want to save money you could go for this 9800GT:
http://www.ebuyer.com/product/173758
Alternatively get an X3 720 instead:
http://www.ebuyer.com/product/159071
It has one less core than a X3 925 but the same clockspeed. The X3 720 also has an unlocked multiplier meaning it can be overclocked easier and some have unlocked to quad cores.
For gaming use I would rather get the HD4850 and an X3 720 than a X4 925 and a 9800GT.