I had two SATA Raptors (10,000rpm) in RAID-0, I can tell you that RAID really doesn't make much difference unless you're going to link 4 HDDS and use it for some serious read/writing :P

I just use them as two seperate drives now....

Just because its SATA150 doesn't mean it'll start writing at 150mb/sec, the best hard discs write at a max of 60 (SCSI)