That motherboard will only accept DDR2. DDR just wont fit. I would get DDR667 to fit that motherboard, as that is the max it supports.
Other than that, it looks like a pretty nice computer. You definitely wont be dissapointed.
You might want to consider a motherboard that doesnt have onboard video if you are going to use a separate video card, like this:
Whenever you get a comment that goes something like, "Intel sucks, AMD rules" just ignore it.
If you want to have a look at the pros and cons of Intel vs AMD go to the top of this section and look at the thread.
The best way to cut through the fanboyism is to do your own research when it comes down to AMD vs Intel.