You posted over a month ago and just joined but in case you are still wondering, most video editing software does not run better with better/faster video cards and none support SLI. After Effects and some other programs will use the video card processor during rendering, but even then a mid-range video card is just as good as high-end card. Check to see the recommended video card for the NLE you are going to use.
Video editing is CPU, RAM and hard drive intensive. So you want the drive where you are editing to be different than the O/S and the faster and usually the bigger the better. So two 500 GB drives in RAID 0 gives you both fast and big.
HOWEVER, do NOT store ANYTHING you want to keep on a RAID 0 array. If either drive fails, you lose ALL the data on BOTH drives. You have twice the odds of this happening with two drives.
Store your original work and anything you may need to make changes some where else. If this is a business, store it in two different places.
The actual burning of the DVD is NOT resource intensive. You don't burn until all the editing/rendering has been done.