Funnily enough I spent a few hours on Friday researching this and came to the conclusion, based on lots of website reviews and forums readings, that the best bet is either a Seagate 7200.10 or a Western Digital Caviar xx00KS. The Seagate ES versions are server editions and has compatibility problems with some home RAID setups.
So go for one of those. The old Spinpoint P series was meant to be great, current ones not so good, the next T series drives are meant to be very good though...
DM