Everyone is going to tell you different based on their personal experience with a very small sample size. FWIW, the main brands -- Seagate, Maxtor, Western Digital and Hitachi -- are comparable in performance and reliability. I personally prefer the Seagate Barracudas with 5 year waranty. Anecdotally, we have seen a higher incidence of failure on Maxtors, but as I mentioned, the sample size is too small to indicate a trend.
Make sure, whatever drive you get, that you get the 8 Mb cache version, and that you get the full manufacturer's 3 year warranty (5 year on Seagate) in writing. You don't want a 'pull' or OEM drive that is not supported by the manufacturer.
Thanks
Trevor
CanadaRAM.com