Well my advise is a bit different then the others, here is the order in which to spend monies:


SSD (get the revo its a PCIe ssd 50G is only $300)
1-2G video card 460 or better (if you go amd I think they have 2G video)
8G Ram (more no longer needed with 50G SSD)
Win7 64bit
X58 motherboard (or p55 or whatever it is) with 920 chip if you go intel

if you go AMD Im not sure but get the motherboard chip with the fastest data trasfer rate between the PCI buss and the ummm well with the ssd on the pci buss that changes a lot of things I need to find out where the DMA controller is. Anyway you don't need a super fast cpu, 3.0GHz is fine and number of cores, in my opinion, is meaningless.

The slowest part of all systems is getting the textures from the wow folder to the video card. So you want the SSD drive (or system ram) and you want a fast PCI path (but the PCI path speed is the same for Intel or AMD .... ), and you want 2G on the video card if possible because then you obviously need to do less transfers. Getting the $300 revo and a 2G video card is your first priority and then I don't think its going to much matter how fast the processor/mb is.

Your GPU will determine your FPS based upon your effects.
Your Ping will determine if your FPS accuratly shows where characters are.
Your GPU/SSD link speed will determine your FPS in areas where a lot of characters are moving around.

Your CPU dosnt do much fo anything that is limited.