Raptors are designed for speed, not storage capacity. They easily beat standard 7,200RPM drives.
If you're looking at spending money on Raptors, which are $200 each, you should also check out SSD. SSD drives destroy ANY AND ALL HDD options because they do not have mechanical parts, which slows down the seek time.
Also I've seen computers with 5 SSD drives RAID0'd together, and WOW.
Since SSD drives don't have mechanical moving parts, they are much less susceptible dying, and don't mind being dropped the way HDD's do.
...But since 128GB is $3000, you might be a little limited 😛