HD failures are par for the course no matter what you buy. 2002 was a bad year for me: I had two disks go (not in a Mac, in a PC). First started producing bad sectors (which was pretty much non-fatal to my data, and detected by SMART). The second, replacement for the first, suffered a logic board failure, which is very much an 'Aaaah! My data! My beautiful data!' moment. Especially as it spewed garbage over the IDE bus in its death throws, causing a fair amount of corruption to another, innocent disk.

In general, hard disk life is pretty random: you should 'expect' 3-4 years of life on average if you use your computer heavily. HDs have moving components: eventually they will sieze, or suffer a head crash, or just develop bad sectors.

Apple don't make hard disks, so you can't really blame them when they fail: HDs in Apple computers won't fail any more than HDs in any other computer. Some HDs are immortal, though. You can tell which these are because they either belong to someone else, are too small to be of any use or never have any important data on them (writing important data to them will instantly cause them to fail). A 40Mb disk of my acquaintance looked like it was seized, but actually could be started by hitting it with a hammer. This particular disk was from the era when it was thought that by even breathing too hard in the vincinity of a HD you could cause a head crash, and you had to remember to run 'park' before shutting down, so the percussive maintenance was guaranteed to give anyone nearby a near heart attack. (This is certainly not a recommended way to, uh, rejuvenate a disk with anything that matters on it, though. This particular disk contained a copy of Windows v1.0, so it was somewhat satisfying to hit it with a hammer)