i would recommend western digital. seagate is usually cheaper, but i've not been impressed with the last couple drives i got from them. support is non-existent.
I d recommend Seagate Constellations. I've got 5 Constellations running in 3 comps right now and even the 2 oldest drives are still running like champs - not a hickup.
Had the opposite experience with Western Digital: 4 drives = 2 dead in the same timeframe.
Even worse for WD... the WD drives were external and only running on demand... the Constellations were running internal and were taxed much more heavily. The two oldest pretty much running 24/7 for 3+ years.
The Constellations are a bit more expensive than WD drives however.
Ultimately... with harddrives it's a lot "luck of the draw"... all Harddiscs fail eventually lol. But as far as the Constellations go reviews, customer experience and my personal experience appears to match up... those are some reliable drives.
P.S.: I.e. I followed the advice earlier given in the thread: Reliable/Fast/Expensive Internal (Seagate) drives and large slower economic (Western Digital) backup drives: Result: Lots of Dead external drives lol.
My advice would now be to go for reliable enterprise class drives, always
(Then, when one fails, you at least know it's not because you were going cheap durr.)
