E6600, 4GB ram, 8800GTX, 2x 36GB Raptors in RAID 0 with SSD to host WoW/Data. Follow the advice of plenty of others and just get a quad core if you want to 5-box. Cramming 5 instances of WoW into two cores sucks. The price increase in the system is less than 1 month of paying for 5x accounts, and it'll be MUCH more enjoyable. The difference between an overclocked E6600 (at 3.6GHz) and a stock clock Q6600 was very noticeable. Get the Q6600. Then 5-box. Intentionally building a new 2-core system for 5-boxing is something we've been saying NOT to do for quite some time.