I currently have 1 WD Raptor 150gig drive. I was looking into doing a RAID 0 setup for my OS, but was curious if I would run into any problems by getting a 150 VelociRaptor drive. Will the two drives work fine for RAID 0 or would I need to purchase 2 VelociRaptors?
You could do it with two different drives, but it is not optimal. Personally I wouldn't worry too much about the raid 0. If you want faster load times and boot, wait and get an SSD when you have the cash and you can get a size you like.