i'm building my new desktop using some newer components as well as using some of my current desktop components.
I'll be using my old thermal take case as well as my ATI 4870x2 in crossfire, heatmaster cooler and 2 HDD's & CD drive.
So basically just installing a newer processor, motherboard, ram and hopefully power supply.
I'm jobless at the moment and looking for work, so i will be looking to keep my budget under $400. (I already have a new Intel i7 - 950 LGA1366 from a year ago.)
For my motherboard i have picked out this asus LGA1366 Xeon: http://www.amazon.ca/Crossfirex-Workstation-Motherboard...
I would search your local craigslist or anandtech's for sale forums for a used 1366 board; you should find one for about half the new price, in case you need a new windows coa. That's also cheaper on craigslist. Ditch the sli factor if the price is right; those old video cards are too slow to spend extra for sli; you can get a newer single video card with the money saved and sell your old 4870's to help pay for it. If you insist on new, I would sell the old 950 cpu for around $125 and start over with an 1155 cpu/board.