I'm looking for an internal drive to store samples, and two good value drives seem to be good locally. Both Maxtor... here are the specs -
DRIVE 1 - MAXTOR SATA ULTRA - $130cdn
100GB Serial ATA/150 hard drive
World's fastest ATA interface
8MB buffer cache for enhanced performance
Average seek time: < 9ms
Ideal for high-performance RAID
Thin, easy-plug cable for improved airflow
Simple, no-jumper installation
PC and Mac compatible
Seek time and size are the most important aspects. Since they're the same, the cleaper IDE drive wins.
However, make sure that you have enough IDE cables available. If you just have one OS drive and one DVD drive, the IDE should be fine. (Run the sample drive as the Master with no Slave on its cable.) But if you don't have a spare IDE connector, then it may be better to go with SATA (assuming that your mobo supports it). The SATA drive might save you the cost and hassle of an extra IDE board.
On the other hand, when a drives transfer rate maxes out, the head typically has to stop seeking and wait for a sector to come around again on the next rotation. All other things being equal, the drive with the higher transfer rate will experience this less often and dish out samples faster as a result.
My older mobos have only uata onboard controllers so I put both sata and uata plug bays in my newer machines. Which I use with 120 and 200 gig Seagate satas and uatas with similarly matched seek times. I've learned to avoid the uatas for high-demand sample libraries. I use them pretty much exclusively for moving stuff between older/newer machines or in fw/usb drive cases shared with laptops. I have a sense that the days of the uata are numbered and at some point their prices will start to rise as they get harder to find.
A cautionary tale however. I've used several hard drives, including several Western Digital drives and will never purchase one again no matter how much money I save. Why? Because among other things I had one of their drives fail on me in the first 48 hours of operation, another fail a couple years later only to be replaced by 2 or 3 bad drives from the same company before I finally got a drive from a different manafacturer to make the system work. That's unacceptable from my standpoint.
Keep in mind the big picture: Even cheap labor repairing a computer is going to start at $35/hr in a metropolitan area for a guy that knows what he's doing in the U.S. in a best case scenario. Then take into account downtime, shipping costs for a replacement etc. and the damage done if files aren't backed up and a hard drive should be the LAST place you skimp on money.
I say, keep those things in mind when buying a drive. I personally would reccomend a Maxtor or Seagate, though I'm sure there are other good candidates. But I would warn against getting a Western Digital for sure. Even if lots of people have good luck with them, you're still playing more of a #s game then with the others as far as I can tell.