With the Raptor drives you have to ask yourself if saving a few seconds is worth it for their high price.
I'm not going to sit here and tell you they make no difference.
However I'm also not going to tell you that they are the "second coming" either - those people who tell you that they are just so amazingly quick compared to normal drives are going a little OTT with regards their "real-world" performance.
In a 20 second disk transfer you can see a saving or around 5 seconds.
So whereas you'd wait 20 seconds on "most" drives, the same transfer can be done in 15 seconds.
Your average game/application will load that bit quicker - but on the right machine they should be quick no matter what.
So what are you getting - something that does make more noise (I'm sorry guys but come on Raptor owners, don't lie here - the drives do make more noise when both idle and seeking).
You are getting a performance increase, a saving of up to a few seconds on those longer disk transfers.
However you also need to look at some simple maths:
Raptor 150GB - £160
Seagate 500GB - £130
WD 500GB - £150
Samsung 400GB - £100
Is that kind of performance gain really worth to you the loss in capcity you can get for similar cash?