That should be really good for just about any game out now days. If all you want is to max out WoW, then you can get by with less than that, but you said you wanted the best rig for $700, and I feel that you wont do much better than that. It did go a little over, my total before shipping was $720. But for an extra $20 you are getting one hell of a computer.
The 4870 1GB performs the same and costs $50 less for around $150. For $200-$210, you can get a 4890, which performs 20% better than the GTX260. Or get a DX11 supporting 5770, which performs the same as a 4870 but uses less power/energy and costs about $170.