@ RAIDing drives:
I assume you're talking about getting another 150GB Velociraptor and RAIDing it with your current Velociraptor (not Raptor)? I'd say go ahead, I've got a RAID-0 going with my two Vertex's, and it's amazing. I would, however, qualify that with a word of caution. If you RAID-0 your OS/Apps drive, BACK IT UP! If one of the drives in a RAID-0 dies...you're kinda screwed if you don't have backups. So, if you do decide to do that, do yourself a favor and go grab a nice 1-1.5TB drive, and use scheduled backup software to grab an incremental image of your drive every day or so.