professorhat:
I wouldn't buy secondhand personally - not worth the risk when new ones are so cheap these days. My personal recommendation would be a Seagate drive - they're renowned in the IT world as one of the most reliable and most of the drives come with a 5 year warranty (edited this after reading comments on my Amazon link below - however, as it shows
here, the FreeAgent Desk drives do come with a 5 year warranty). I have three!
You can get a terabyte version from Amazon
here for £85 but I haven't done any shopping around to see if it's cheaper anywhere. As mentioned though, you really should get two for backup reasons. It depends on how much music you have of course, but once you've ripped them all once, the thought of doing it again strikes terror into the heart!
Plus, i believe that Maxtor and Seagate drives come with a "re-badged" copy of Acronis True Image back-up utility (i was looking into this only yesterday). More a point of interest, but i further believe that ont of them (Maxtor or Seagate) now owns the other, or they have an equal arrangement. Anyhoo, point being theyre both very well respected and now connected...
Muggins here has a Western Digital. I was somewhat less well informed at the time...
EDIT - i get the impression that backup software appears more on drives bought for PCs rather than external drives, but i did find a couple examples of externals with it, i think.