Upgrade office computer with onboard RAID

[beatarmy]

Current system:

Pentium D-840
AW-8 MAx
2x WD-Raptor 74 gb in RAID I using onboard ACH7
2x Caviar 300 gb in RAID I using onboard ACH7
Seasonic 430 watt power supply
Corsair xms2 2gb ddr2 pc800
ATI firegl v3100
onboard audio
running Win XP

I mostly run: Photoshop, DXO, dragon naturallyspeaking,
My budget: $2,000 plus monitors
When I will build: Immediate
Where: CONUS


What doesn't work: currently unstable with occasional memory errors on both sticks. Is this memory, mobo or power supply? I dunno. I don't have the time to explore.

I want:

Dual monitors, each at 1600x1200,
maximum cpu/gpu/memory speed for large photoshop files
stable.
Vista business 32 bit clean install. (Current OS has been continuously upgraded since Windows 2k across 3 machines. I can only imagine what the registry looks like. naturallyspeaking won't work on 64 bit for a while yet.)

My thoughts:

CPU: I am pretty much set on quadcore for photoshop and DXO: QX9550
Mobo: I don't know whether I can have two large high res screens off one GPU, so want paired video cards. Your thoughts on most stable board (I don't overclock).
memory: 4gb ddr2
Disks: dual velociraptors and dual 500gb caviars
DVD: bluray burner
Video: paired firepro 3700 or 3750 if available
Raid: onboard or a separate controller. I appreciate your thoughts.
Power supply and case: something quiet.

All help appreciated

 

[Roguestar]

Why would you buy the QX9550 when the Q9550 isn't nearly as expensive and does exactly the same, seeing as you're not overclocking?
Two high res screens off one GPU on a single card is doable for most video cards up to something like 2560 each, IIRC.
Velociraptors are very expensive for the relatively small performance difference you get between them and the best 7200RPM drive, which is incidentally both cheaper and a 1TB drive with much more storage. Don't forget to have a backup solution and not rely on RAID-1, which as a mirror, will duplicate any accidental file deletion or virus problems. An external drive is a safe bet. If you want to run RAID-1 to minimise downtime in the case of a single drive failure (because that's all you're protecting against) then most decent motherboards have RAID onboard or RAID variants in the product line. A standard Intel P45 chipset board such as the Gigabyte EP45-DS3R will do that, and has two graphics card slots.