Personally, I would go with an i7 950 for the CPU and one GTX 570 as the graphics card. Multicard solutions for video editing can be troublesome, in my experience. Also, ATI drivers have frustrated me so many more times than most Nvidia drivers have.
HDDs ... $2000 really wouldn't allow room for any SSDs unless you used a very small one for the OS and video editing programs. For mass storage you might want to go with a few 7,200 rpm drives with at least a 32 MB cache, although a 64 MB cache would be ideal. The black versions of WD drives hold my respect. Perhaps this would be a good time to go for a redundant RAID 1 setup.
RAM ... tri-channel DDR3, of course, but I am honestly not sure how much you'll need currently or a few years from now. A good brand of 6 GB (2 GB x 3) or 12 GB (4 GB x 3) should work nicely.