The hard disk mate, buy a Hitachi Deskstar. you will get more gig per buck and better performance, they often beat Raptors in speeds tests.
Hitachi Deathstar? I've always had bad luck with those drives. Has their reliability increased? Will have to check some reviews.
Just gotta throw my opinion in here.

You are right to call it the Hitachi Deathstar they are terrible drives imo, speed certainly isnt a trade off for reliablity imo especially when it comes to hard drives.
Raptors have nice specs but the performance of the Western Digital drive you mention is too good to pass up and is currently the fastest 7200RPM drive out there.
I did extensive research before getting my new 500GB drive the model number is WD500AAKS the AA bit is important just KS and it means its got more platters which means more heat and less speed.
They are still of the same range. AFAIK it's only the 250GB that comes in AAKS and KS.