Hmmmm... I just realized... recording eh? You now need a break-out box and something sorta-highend from creative to do the job... drop the e6600 down to a 6300, save you 200 bucks, and get either an X-FI Plat or an Creative E-mu 1212m. The X-FI play comes with a breakout box, runs about $160, the 1212m is Creative's proffessional line of audio units, with some of the best ADC. Your choice on this.
You don't need a raptor, since its a lot of money for marginal performance increase, just get 2 of the 320 gig Seagates. The money you save on non-raptor will put you back up to the e6600... or even a better graphics card... your choice.
One more thing, I just realized the P5B doesn't have firewire... might need to buy a firewire pci card, but thats dimes and nickels.