On the 10th AMD will be showing off the HD5xxx series GPU. Current rumors are that the 5870 will be about the same speed as a 4870x2 and be around $299. The HD5xxx series can also output to 3 monitors at the same time which might be something to think about.

Intel are also releasing the i5 CPU which will be on a cheaper motherboard than the current i7's so it might be worth waiting for that to see how it performs vs the i7.

I would defiantly get a raid0 SSD array though because that can increase frame rates a lot in places like Dalaran.