New Multiboxer.. hardware question

[Ualaa]

If your motherboard takes ram in sets of 3's, go to 6gb.
If your motherboard takes ram in sets of 2's, go to 8gb.
You can always upgrade to more ram down the road, if you want more for some reason.
The DDR3 ram is comparably priced to the DDR2 at the moment, and 3 > 2 by a large amount.
Any brand name ram will do, I particularly like Patriot and Mushkin, but Corsair is good too.

I like the i7 920 the most.
Not overly familiar with i7 860 or i5 750.
I'd look at the motherboard types for each, particularly the type of ram you can use and what processors the board will accomodate, should you decide to upgrade in the future.

[alcattle]

for the most part Ualaa is right on. The i5-750 is currently the best gaming bang for buck CPU. Will do great on WoW and most others. P55 motherboards are pretty close. Gigabyte and Asus are slightly ahead. 4x2G 1333 RAM will be fine, although it fills up most boards. 4 gig stick are starting to come down, but are still double the cost. Get a decent GPU and a SSD and you are set. You can try the 9800, but you will be upgrading that before long, I would not buy one now.