I would not set up a single RAID 0 array in that configuration for several reasons. (1) the RAID 0 becomes a single point of failure for your whole system. If you loose one disc you loose everything! (2) You want your OS and programs physically separated from your video files. The RAID 0, while faster, will still have the potential for the disc heads for the windows swap file and your video files to be in contention. (3) Having a separate OS disc makes it easier to backup and restore from bare metal if you have a catastrophic failure.
I would use separate drives for OS/Applications and video. Eventually you can set up a RAID 0 just for your video files if you feel that file I/O is a bottleneck to editing. More often than not, you will be CPU bound unless you are working with uncompressed video and a RAID 0 will be unnecessary.
~jr
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