lack time for thorough read of replies, but my .02 centavos:
paraphrase: "win people need the reassurance hdd will run on 2k,xp, vista etc"
yeah, though sata/pata/mobo compatibility (for internal hdd) is what matters :-/
i haven't maintained lots of pcs, but had bad luck only with a 15gb deathstar (infamous, but brief, lemon era). it died at 17 months of ~24 hour per day powered on, with infrequent active usage.
I've had second hand pc/mac where hdd died, but no idea of hours used, since all were OOOLLLLDDDDD (crackling creaky-boned, cobwebs smothering the synapses, whipping young whippersnappers with the cane, i remember when a 1 pound candybar cost only 2 cents and we didn't even have gas stations - we had to wring fuel out of our own earwax, my allowance was only 3 pennies a year, you should feel grateful to even have raw garden slugs & pine bark to eat twice a week, where are my d@mn pills?).
(as of ~2004, the last time i bought hdd) i chose seagate only for 3 year warranty vs 1 year for other mfrs.
only desktops until recent years (so no experience with laptop hdds)