I have always wanted to build my very own SLI desktop and now that I have worked hard to gain a considerable budget I have found it even harder to decide upon which components are best suited together.
I am thinking of using the Corsair 800D chassis with my components centered around the Asus Rampage III Extreme Motherboard and a 850W Gold PSU supply. The H50 Liquid system from Corsair will be ideal for my first build in terms of CPU cooling.
I having my most difficulty in deciding on GPU's, Memmory and Storage. Maybe 2x GTX560? Or a Sli GTX480 since they are considerably cheaper then the GX580.
Can you guys suggest some components that would be ideal for a budget of £2000?
SLI isn't necessarily the best way to go. Do you plan on upgrading in the future? What is your primary usage of the system?
I'd recommend a P67 base if you're gaming. Get an i5-2500K or an i7-2600K (if you need hyperthreading) and overclock it. The new processors are much better at gaming than the i7-900s, but if you're doing any other work, it may not be the CPU for you.
There are better coolers out there than the H50, and they're also cheaper as well. It's not necessarily a better cool just because it's liquid. I have a Cooler Master Hyper 212+ ($25 on Amazon) and I never hear it (CPU never goes above 25% usage) and my max temp at full load has been in the low 50C range.
The 800D is a pricey case, and you really only get the most benefit out of it if you watercool the entire rig. I would recommend something along the lines of a Cooler Master HAF 932 or the HAF X; they're cheaper and designed better for airflow.
I agree on the SSD - you'll see more utilization of that than a $300 case. Your OS will seem much snappier, and you'll have enough room to throw a few programs on the SSD as well. The OCZ Vertex 3 has been announced and should be released soon.
A fast storage HDD is the Samsung F3 1TB; it may only be SATA II, but it's just as fast as the SATA III hard drives WD has out right now, and about $25 cheaper.
As for memory, you'll want a good set of 6-8GB with a low Cas Latency (6-7; 9 is high) and speeds around 1333-1600MHz. For P67 boards, get a 2x4GB kit; for X58, get a 3x2GB kit.
Now for GPUs. Don't even consider the GTX 480s at this point; you shouldn't be thinking about buying older GPUs just for SLI since you're starting from scratch.
If you do plan on adding to the system later, leave the 560s alone and get one GTX 580, and add another one later. If you buy 2 560s now, you won't have any room for upgrades and you'll only have the equivalent of about ~1.25 580s.