I too have my doubts as to multiple drives (6 as far as I can tell in your spec) will work effectively, but they will generate noise (some) and heat (a lot) which in turn generates more noise. I don't like too much noise from a computer these days, must be getting old(er).

Some more thoughts:

RAM: do you need extra fast extra hot ram? How about 8Gb of slightly slower speed, slightly cooler good quality RAM instead?

Case: A BIG case for airflow and cooling, if you are running multiple drives, hot RAM and a qaud cpu you WILL need it.

Fans: 120mm fans, preferably low noise ones, maybe you will get some with a decent case, I use a self modded (for less noise, better cooling) Antec 182 (I think :P), but I am not entirely satisifed with it, I feel I need a bigger case with the stuff I have in it (3 HDD, 4GB RAM, quad cpu and 8800 GTS vid card).

HDD: I would rather go for a bigger HDD as they have higher data density, which tanslates to high read/write speed a lot of the time, I would say 1 drive for OS/random stuff and a seperate drive for WoW/other stuff, a couple of 500 GBs would work fine I am presuming, if not larger :P This means you don't run out of SATA headers on your Mobo too, a lot don't like having more than 4 used for HDD, or at least that was my experience recently with one Mobo.

CPU: The old staple of Intel Q6600, or perhaps the newer fabbed one? This: Q9450 then leave alone or overclock.

Motherboard: I use a Gigabyte GA-P35-DS3P in my machine and I like it, was good for overclocking, and seems stable and well made, kinda went off Asus after they kept breaking. There are newer chipsets out there though, and after having had trouble with Nvidia chipset motherboards I decided to use Intel now, and why not, I am using an Intel CPU after all... X-48 is the current top performance chipset from Intel atm isn't it?

CPU Cooling: How are you cooling? If it's Air cooling, I use a thermalright something... Xp-120 maybe? decent cooler, but there are others out there that are also good, whatever is the best cooler for your money basically. Quad core CPUs tend to not be cooled equally across the cores, you may get a temperature differential across them of 10 C or so, at least mine is like that and I couldn't be bothered to reseat my cooler for the nth time in the end.

PSU: a GOOD one. I like Enermax, but they are pricey, even by premium standards. The other makes mentioned so far are also good, try and get one with modular cables, will make your machine less cluttered and easier to put together (he says). Had a PSU blow up on me and took out all my PC components too, in the middle of raiding in EQ on top of it... I will only use a good brand one from now on.

Graphics card: How about the ATI 4850? My only concerns are the limited cooling it has.

That's about all I can think of for now, sorry for Wall.