The Velociraptor is much faster on things like boot time and on loading application to memory, and putting this on RAID will be a bit faster on things like copying file and time to load and save large documents.
Even two WD Caviar Black 500GB on RAID 0 would be far better than One WD VelociRaptor 300GB (but you opt for 150Gb?)
I am thing about 2 1TB drives at the moment, but it is kind a cool to have the bragging rights of saying "I have a WD VelociRaptor in my computer"
That pretty much just means "I wasted money". You want real speed an SSD is the only wany to go. They have got too cheap here lately to make a 10,000RPM mechanical drive worth it. In real world situations the 7,200 RPM 500GB per platter drives were almost as fast as the Raptors/Velociraptors anyway.
Hmm maybe I wont get the Velociraptor, How fast was that 2TB drive? I am guessing it isn't a 7,200RPM because they have all of the green stuff built in?
Did that 2TB WD Drive just come out? there isn't even a review on it yet at newegg.
Hmm maybe I will get both that 2TB and the 1TB I have a 1 TB drive already so I can Raid the 1TB drives and use the 2TB for storage or something.
If you have the budget get a 120GB SSD with a Sandforce controller. The Crucial C300 , GSkill Phoenix pro and OCZ Vertex 2 are all about egual and you can find one for ~$200. Then get a 1TB Spinpint F3 cheap from here:
If it's a choice of a Raptor/Velociraptor or save money for an SSD I vote save for the SSD and just get a fast 7,200 RPM to last until then. The Spinpoint F3 has been the best "bang for your buck " for a while now. 1GB versions have been running in the ~$60 range.