Making up a number for arguments sake. For those that don't read well and will argue later, I will say it again... I MADE UP THE NUMBER... 😉
Say that a Raptor might improve your performance by (***WARNING*** This is a number used for an example and may have no real relation to reality) 4 (the made up number) percent. Is a 4% (see previous notes) worth it to you? Total cost is cost plus wage*time. So, if you make $4 an hour and a Raptor costs (using Newegg prices) $2.38 per gig while a WD 200GB SATA costs $1.12 / GB. To get 200GB of space with Raptors, it would cost $476. A WD 200GB SATA costs $179 (including the 99 cent shipping until April 4). The difference is $297. At $4/hr, that would take 74 hours + of work to make the difference. If you use the computer for 200 hours time .04, equals 8 hours. 8 hours is not 74 hours, so totally not worth it (Yes, just a rough comparison).
Fark, spent too much time on this anyway... Is a small performance gain worth the price? You have to decide. It was for me, but that is because my computer makes money. It could be argued that 15k SCSI-320s are even a better deal in my case, but I am not the federal government and can not pass a law to allow myself to spend more than I have. 😉 The ultimate decisions is yours and the best we can do is reduce your dissonace over the decision. But, it will give you a bigger e-Peni, so that might influence your choice too (but some will laugh at such over-compenstations behind your back - at Anandtech, they will do it to your face.)
😀
Edit - Did I mention that I made up the 4% number? 😛