$110 - MSI Motherboard
(LGA 1156, not for OC)
$280 - Core i7 860
(LGA 1156 w/ HyperThreading)
$90 - GSkill 2x2GB Ram
(DDR2 1600, 4GB Dual Channel)
($80 x2) = $160 - Western Digital Caviar Green 1TB
(Two of these in a RAID array)
$150 - Antec Twelve Hundred Case
(Case doesn't really that much, its really all personal preference)
$110 - Corsair CMPSU Power Supply
(Way more than enough)
$250 - ATI 5850 Graphics Card
(Extremely powerful, a great deal)
= Comes out to around $1200 (w/ shipping)
From my experience video editing seems to require a fast hard drive, a nice multi-core CPU, and quite a bit of harddrive space.
This is what I would buy if I were in your position. If you wanted to shave a few bucks off the final price then I would suggest going with just a single harddrive and not pursue a RAID array. You could also get a cheaper case.
Raid is simply a way of using two harddrives at the same time to nearly double your hard drive speed.
Now, more than likely your wondering why I recommended a graphics card even though you aren't gaming. That is simply because many professional video editing programs and applications can take advantage of your graphics card and improve overall performance. Which begs the question: What programs do you plan on using?
Hope this helps, I have to go get some sleep now!!