Definitely get the 10k HDDs. 2 of them in raid0 work fine for gaming because of the high HIGH performance, but you don't get the security of redundant storage. I don't feel this is an issue on my gaming rig, so thats how I'm set up.

We have seen some slight problems with mulitple video cards and multiboxing WoW, as described in these forums, and elsewhere. WoW is a 32 bit application, and even if run in a 64 bit OS, Warcraft can still only utilize a maximum of 4GB total RAM. If you allocate 1.5GB of that just to your video cards, you will only have 2.5GB left for the system to use for the OS, WoW, etc. This causes the machine to use the pagefile.sys (virtual memory) and it will really work your hard drives.

I have personally seen a machine with 2 x 8800GTX 1GB video cards have a performance boost when the second vid card was removed simply due to the better RAM usage.

But really, you're not speccing this machine for WoW. It looks more like a Crysis machine, to me.