Personally, my dream is 3 hard driver, two 40 10k rpm in raid 0 and then another internal hard drive of some large size. Another problem is in his set up he isn't taking advantage of 'SLI'. It is in my opinion that ATI's crossfire is superior to nvidias SLI. But of course you want a motherboard that has a chipset that is appropriate for the crossfire setup and that will do both pci-e slots at 16x at the same time. From start to finish, you can spend between $2000.00 - $10,000.00. Knowing how much a person can spend will vary greatly upon what parts a person can/will choose. So when you look at the price difference of a sata II or a IDE hard drive, you have to know what a persons spending limit is.

SLI and Crossfire are a waste of money...
I had 7800GT SLI...and my single 7900gt (not even next gen card) beats the **** out of it....there's just no point to it, because you need to spend close to $800(AU) each card to get the latest and greatest video cards in SLI/xfire...and then the next video card that comes out beats it...

Waste of money (and look at my computer..it's built for gaming...150gb raptor, 4 other hard drives with 1 dedicated to the page file...a 120gb drive at that )

Yessir... I agree-- but the price difference for HD's is not that much-- IMHO. In fact here is a page for example-

Buy Hard Drives, External Hard Drives and Laptop Hard Drives Online at Newegg.com

WD 250 gig IDE = $69.99
WD 250 gig SATA2 = $ 69.99

Whats your budget hoodie because i would recommend moving up to a dual-core processor.

well my buget was £500 to £600 and possibly £700 if money can be borrowed mooched power raised ect.

i would say, just keep saving.
Especially right now - DX10 cards are almost released, infact i heard that there is one being released next week here in Western Australia (not sure on the validity of that statement...it could be very very wrong).

Hold off until they come out, as it will push the prices of the current video cards down.