I've got boxes of dead hard drives in my shop that I keep around for board/part swaps when I'm doing data recovery.
My experience with hard drives (and, as is the norm, it differs from others experiences) has been:
1. Excellent results with WD. I have the lowest rate of failure with WD drives. Their RE2 drives are excellent quality, with a 5 year warranty. I have had ONE die in the last year, and it was within a few weeks of deployment, and was actually the mirror drive on an array. WD's Notebook drives have been excellent as well.
2. Excellent results with Fujitsu's Enterprise SCSI drives. Not so excellent results with their old desktop drives. I remember their 20 and 40GB 5,400 and 7,200 IDE drives failing by the bucket load, all within a relatively short time frame. This was shortly after they stopped producing desktop drives. Their notebook drives have about the same failure (or the lack thereof) rate of the WD Scorpio Notebook drives.
3. Seagate drives have been good to me. Very low rate of failures. I was sort of disheartened when I found that they had purchased Maxtor, as I have always regarded Maxtor as a sub-par drive, as they have, besides the Fujitsu fiasco with the desktop drives, been my highest rate of failure drives. The majority of drives in my parts boxes are of the Maxtor variety. Seagate's Enterprise SCSI drives, such as the Barracuda and the Cheatah have a spotless track record with me. I still have a number of these things kicking around. They were LOUD, but reliable. Only had a few Seagate notebook drive failures in the last year or so.
4. Maxtor. As mentioned above, not great results. They purchased Quantum, who also used to make some rather sketchy IDE drives. Their (Quantum) Enterprise drives I had very good luck with back in the day though.
5. Hitachi. Pioneered the 12,000RPM drive after Seagate was cleaning up with their 10,000RPM Cheatah drives and hadn't done the 15K drive thing yet. Good luck with their Enterprise stuff, recently had a number of failures with their larger laptop drives. Better than Maxtor, but not as good as WD in my books in terms of notebook drives.