Its not always beneficial. I used to run my OS on a 2x80gb raid0 array. I gave one of the 80s to my sister when I built her pc and I didnt notice much difference from the raid0 in gaming or system performance. I now have 2 raid0 arrays 2x400 and 2x500 for storing extremely large media files and transferring them from one array to another is extremely fast, but my OS is on a single 400gb drive. I also have another media center PC with a raid0 array. Everything is hooked up to the gigabit network so I get excellent speeds there.
Now a friend of mine has 2 raptors in raid0 for his os, and his system does feel a lot more responsive. I havent benchmarked anything on there so I dont know that his performance was definitely better, but it did feel quicker. Im sure even just one raptor would improve the responsiveness due to the extremely low seek times, but even so, i would recommend your option #2.