Just registered to post this. Basically, here's the scoop. I read the review since I was building a new system and didn't want to spend huge bucks for the Raptors with so little storage space, and I decided to buy 2 of the 160 gig drives for SATA RAID 0. After a few days, I started noticing the cat-like meowing of the drives every so often which started to concern me. Here's what I've done:
I used Drive Image to copy all my stuff over to my WD 80 gig special edition and formatted the 2 Hitachis. Then, I unplugged the power from one drive at a time and listened for any noises they might make in Windows. Sure enough, both drives make the meowing noise every once in a while. In my case, it's pretty often, and I think I've narrowed this down, to some extent, to the fact that I have 1 gig of RAM. For that reason, the drives are rarely used for the page file, if ever. Since they aren't being hit unless I'm opening programs or something, they tend to idle alot, so I hear the noise. Also, my case is extremely quiet, so it's a lot more noticeable than it would have been a long time ago.
All in all, these things turned out RAID 0 HD Tach benchmarks slightly faster than my friend's RAID 0 Raptors, and fly through everything I throw at them, so I think I'm gonna stick with them. As long as I know the sounds are apparently normal and not signs of failure like my old 75gxp, I'm not too worried about hearing it every now and then.
Sorry about the rant, but I just wanted to put my 2 cents in after finally finding some people having the same experiences here. Now, I'm gonna go re-image my stuff back to the Hitachi array, boot times are killing me now that I've been spoiled . Drives are highly recommended despite the noises, so don't be too scared to take a shot at them, especially if your case isn't super quiet.