I currently have a Seagate Barracuda 7200.10 400GB ST3400620AS SATA-II 16MB Cache - OEM drive, however I am not impressed with the sounds that it makes, which accoriding to Seagate are normal operation. It looks like I got one with the white glue on the motor which appears to be much louder than the drive with the pink glue 
I have been looking to purchase a Western Digital 500GB drive , but I am not sure which one to chose from:
Western Digital Caviar RE2 500GB 5000YS SATA-II 16MB Cache - OEM
or
Western Digital Caviar SE16 500GB 5000AAKS SATA-II 16MB Cache - OEM
I have been looking to purchase a Western Digital 500GB drive , but I am not sure which one to chose from:
Western Digital Caviar RE2 500GB 5000YS SATA-II 16MB Cache - OEM
or
Western Digital Caviar SE16 500GB 5000AAKS SATA-II 16MB Cache - OEM