My next will be a Western digital RAID edition 2 drive. They are rated for continuous heavy use and have a long warranty
Just one heads up: Those 'raid' drives are not recommended if you don't actually run them in RAID mode. In addition to the being designed for heavy use, they have one additional 'feature' -- they spend very little time on trying to recover drive errors.
All harddrives have a bunch of spare sectors on them, and when errors crop up (not 'if', but 'when'), the drive will automatically detect this and remap the affected sector to a spare. This can take a couple of seconds. Depending on the severity of the problem, the drive may spend up to 20 seconds or so repairing the damage. However, in a RAID system, such a long delay can cause the array to break and requires it to be rebuild which can take hours... so the 'RAID'-rated harddrives have different firmware that pretty much order the drive never to spend more than 2 or 3 seconds trying to repair itself, to prevent the array from breaking. the RAID adapter itself will then deal with the damage on its own and reconstruct the data on the fly when requested, rather than the drive working around the problem and actually fixing the real problem.
That's nice, but if you don't intend to run in RAID mode, then you really do want your drive to take a couple of extra seconds to save your data for you.
So... While the RAID drives tend to be pretty good quality drives, the fact that their firmware allow for less damage control in case of minor errors it not a good thing for non-RAID users... Those ought to stick with the regular non-raid drives.
(My next drive(s) will probably be a pair of the Samsung 400GB's)