Need help with new computer design

[garytp]

I would like some input regarding a new computer that I will have built for my wife very soon. Neither she nor I play games. She does a lot of digital video work and rendering along with some web and graphics design and a lot of music ripping and burning dvd's.
We also use the system for photo shop and digital photo work.
She uses a lot of hard drive space when creating vidoos and rendering as do I for my digital photo storage.
I want a screaming system that will render fast as well as run several programs in the background for us.
I have chosen the new Conroe extreme 6800 processor, LGA 775 with Corsair twin 4096-8500C5 DD2 memory. I am having trouble deciding whether to run a Crosssfire system using two ATI Radeon X1900 XTX with 512 Mb or to run an SLI system using two nVidia 7900 GTX's.
I had planned on adding the Soundblaster X-Fi Extreme music card.
I do not understand or know if I would need a physics card that I have been reading about?
I was going to use a 250 Gb Sata 7200 rpm for OS and programs and use a 750 Gb Sata 7200 for her rendering and storage, and a third 750 Gb for backup, although she does not want to use a raid system for backing up or mirroring.
I also do not understand about the motherboards as to which one is really the way to go.
I also thought initially that I might as well water cool the new unit but after reading that latest MaximumPC article, I am not sure if it is necessary. Is fans adequate or should I water cool the system?
I will have her system connected to the internet with a cable modem and we use a wireless router with a network to connect my notebook. Right now she is rendering for hours on my notebook. I am tired of this.
I considered building this, but I have never built a computer before. I can barely manage to save files in the right place. My wife is the computer person in the family. I had several people suggest that what I want to build is too difficult for me regarding my computer knowledge. Therefore, I have considered having either Voodoo PC or Falcon build her system.
Can you guys give me some advice as to what I am forgetting or what I should change with configuration. My biggest dilemna is whether to go with a crossfire system or SLi system.
Thanks
Gary

[Steve B]

i know other people are already answering your questions, but let me start them off by saying welcome to the forum

[kasavien]

Hmm where to start. From personal preference Crossfire would be the best option and i'm fairly sure they perform better on the intel chipset (than nvidia). ATI are about to release a new card - the 1950XTX i think, something like that anyway. It will be quieter and faster than the current 1900XTX and is aimed at beating the 7950GTX too.

Water cooling is prety much pointless unless you plan to overclock the system, air cooling should be more than sufficient. The only other benefit of watercooling is it obviously produces less noise, but then again you can get low noise fans which will do just the same.

I'm not too sure about motherboards for this setup, its not something i've really looked into. Maybe someone else can comment on this

Most people on here will tell you to build the system yourself, it will certainly be cheaper, and is not too difficult if you are good at following a manual. Personally I prefer to have a built system as there is technical support if anything goes wrong, and if you pick the right company you are guaranteed to get an optimised fully functioning machine. If you want to persue getting a pre-built system and you are in the UK i can highly recommend 3xs.scan.co.uk, they built mine and it is top notch and their customer support is impeccable. Other companies i've heard good things about are Voodpc, Armari and Falcon, but i'm not sure what their markup is. The reason i chose scan was that their markup was fairly reasonable, i think they charged around £150 more than the components cost for the system.

Hope this helps

Andy