This is a common misconception, but two drives in RAID 0 do not have faster access times than a single 10,000RPM drive, plain and simple.
In theory a RAID 0 should allow half the access time to be obtained, but this is if you take into consideration that this is making reference to the burst speed. Drives will never perform anywhere close to this burst speed meaning that although a RAID 0 array may decrease access times slightly, it will only be by one or two seconds at most.
If you haven't gotten the hint by now, we'll spell it out for you: there is no place, and no need for a RAID-0 array on a desktop computer. The real world performance increases are negligible at best and the reduction in reliability, thanks to a halving of the mean time between failure, makes RAID-0 far from worth it on the desktop.
and you can judge the true performance benefits of RAID 0 in a realworld enviroment (aka not SiSandra burst speed benchmarks) and answer the question yourself. Unless space is an issue, a Raptor will always be faster than any two 7200RPM drives in a RAID 0.