I've used a lot of hard drives over the years. Like you, I use WD and Samsung for most of my builds. I have used Seagate, Maxtor, Hitachi, Fujitsu, Quantom, and the old IBM Deathstars before Hitachi bought them. Here are my personal experiences.
Seagate: You got to take into account Segate offering 5 year warranty on all their HDD. I didn't have good luck with Seagate, and most of the people I ran into had the same feeling. It has been since 2002 since I've used Seagates so they may have got better. I always thoght Seagates Hard drives ran hotter when compared to WD. I had a Seagate 160 GB PATA drive, hooked up to the same system that a WD 160 GB PATA was hooked up to. I felt of both of them, and the Seagate was considerably hotter.
Maxtor: I had plenty of Maxtors die on me after about a year of use so I quit using them. I bought myself a 80 GB Maxtor drive, and it didn't last that long. I also had two friends have Maxtors fail on them. One was a 250 GB drive, and I cannot recall the other.
Hitachi: A lot of the guys on newegg rave over how fast these drives are. I got the same exact 80 GB SATA drivers that newegg sells in about 20 Acer computers. These hard drives make loud clicking noises, and are noisy drives. I would not ever use one in a personal build, or recommend using these.
Samsung: Quitest drives on the market I think. I've used Samsung almost exclusivly since buying my Samsung 160 GB PATA drive. That same drive is 4 years old, and is running as fast as the day I bought it. Out of all the Samsung drives I've put into builds, I've had one drive fail on me. It was a real odd problem. When it died, it would not let the system boot up. I put it into 5 different motherboards, and it kept the PC's from booting up. Overall though, I am very satisfied with Samsung drives.
Western Digital: Very good drives that I have had good luck with. I got a 2 GB WD drive that still works. The WD's in my acers are night and day compared to the Hitachi's I got with my last batch. Always had very good luck with WD.
I'd rate them like his .
1. Samsung
2. WD
3. Seagate
4. Maxtor
5. Hitachi