Are you goingto run PCIe based hardware like MojoDX, MXO2 or AJA on your system?
If you are,DO NOT BUY A SANDY-BRIDGE System. The P67 chipsets have shared PCIe bandwidth, so each slot does NOT have its own dedicated PCIe lanes.That means trouble.You don't want that.I do not know for sure for the Z68.
On the other hand,SINGLE xeons are not better than 2600k in rendering options anymore.Here is what is
present
A DUAL XEON though, will be like a ferrari in a drag race with a buggy.A lot of money,but worth every penny of it.
This baby has six cores(2600k->4) and if you put two 12(2600k->4) ,each processor has 12MB cache(2600k->8) supports 3 lanes of RAM(2600K->2) and you do not need to throw your computer if you want to upgrade your processor, RAM or quad sli...
In addition,I would not bother with any consumer monitors like Hazro, Iiyama etc and go directly to the professional stuff.Buy an EIZO or LaCie, monitors well known for their distribution of quality in this area.
About your external drives, putting them into an external case that can be connected with a PCI Card boosting your performance.
Finally,this is what i would recommend for the computer without the monitors:
Product Name Qty Price Line Total
2*Intel Xeon X5650 2.66GHz (Westmere) (Socket 1366) £1,498.00
EVGA Classified SR-2 Intel 5520 (Socket 1366) £599.99
MSI GeForce GTX 580 OC Twin FrozR II 1536MB £379.99
Corsair Professional Series Gold AX1200 £224.99
Corsair Obsidian 800D Full Tower Case - Black £224.99
OCZ Vertex 2E Bigfoot 120GB 3.5" SATA-II Solid State Hard Drive £169.99
2*Pioneer BDR-206DBK 12x BluRay RW / 16x DVD±RW Drive - Black £207.98
2*Corsair XMS3 6GB (3x2GB) DDR3 PC3-16000C9 2000MHz £149.98
2*Noctua NH-U12P SE2 Dual Fan Quiet CPU Cooler £111.98
Total : £3,588.12
Then you can upgrade to sli,RAID of SSD and other goodies. Professional Video Editing is an expensive job.If you need to play games,buy an other 500gb hdd and install windows on that.
Good luck!!!!!