thanks mouser and fodder for those replies.
mouser, i can't fault what you say about the dual monitor setup - i've got two 19" crt monitors at the moment but i feel guilty or just too lazy to turn both on at the same time - i need to get into the habit of using both of them.
i also have a further dilema with this new pc build i'm going to do - my main 19" crt monitor is several years old but it was a high quality one when i got it and it remains that way today (good dot pitch and all that), it's better than any LCD monitor (no great achievement there really) but i'm tempted to go for one of these beasts...
Eizo Flexscan s2110w
http://www.eizo.com/products/lcd/S2110W/index.asp it's a 21" widescreen monitor that is getting fantastic reviews - but the price is high, about £700. again i'm prepared to go for this but i really can't fault the 19" crt monitor i've got now. the flexscan is bigger of course but perhaps limited in other ways. i would even go so far as to buy a 15" or 17" or even 19" LCD monitor to compliment the 21" Flexscan. Pure insanity to have dual monitors of this size maybe, but i'm sure i can find a use for such things even if i can't be bothered to use the two 19" crt monitors at the moment.
f0dder, you've certainly given me a few more things to consider. what you say about the Asus board and the way it handles raid is reasuring. the raptor drives are sata even though they are 10,000rpm - they aren't SCSI or have i missunderstood what SCSI can be, i thought you needed a SCSI card for SCSI drives(?).
the iRam thing would be nice (i've read about it elsewhere) but it's not available where i'll be shopping - 4 gigs isn't going to change the world, though, maybe when it gets into double figures.
i certainly agree with you with what you are saying about raid 0 and start up times for programs and the operating system. whilst sat in front of the computer i tend to drift from one program to another to another and then another, so i'd certainly appreciate quick loading times. loading in game levels quickly would be nice also. video i don't really know - editing videos of several layers would be easier(?).
regarding the hardware i've picked out - it's all chosen on the basis of a couple of UK computer magazines. the quality, performance and noise level all being factors i've looked into - their reviews stating how quiet things are. so, i'm confident things will be quiet - the raptor drives are noisy for sure but if i get them they'll be put inside hard cases that will dampen the noise.
i think the antec p180 case will allow me to put a couple of fans in (at least) to cool the hard drives down.
i've included a spreadsheet if anyone would like to see the specific items i'm looking at ordering.