Just look at it this way. I'm not a WD salesman so it doesn't really matter to me what you go for in the end. I've got three WD HDD's though, and I've had one for around 4 years (main OS drive) and another two 750gb for around a year. They're fantastic! Maxtor make excellent HDD's too.
Also, another point, WD specialise in making hard drives. Samsung don't! They make them, but also make DVD players, Blu-Ray players, plasma and lcd TV's, phones, optical disk drives. And I know from much experience that these products develop faults after 6 months.
I'm not disputing your solution. It seems very good to be honest
And what you say is true; any drive can fail. But when you have MTBF of 1.2 million hours for the WD compared with 600,000 hours for the Samsung, it makes you wonder. Oh and I kindly ask that you don't say that I'm only just quoting manufacturers' times. The fact of the matter is it is unlawful for any company to state misleading things of a product. MTBF are approximate.
Like plasma and LCD tv's, the fact of the matter is that Samsung sell better than other manufacturers' is because they're a little cheaper. The fact that a lot of the people on this forum recommend Samsung because it's cheaper proves my point. Custom PC recommended the Spinpoint model because it is cheaper and slightly quicker than other Seagate and WD drives. Who cares about it being a millisecond quicker! Hard drives are there for long term use, not a year or two.
Doesn't it make people wonder how Samsung can sell so many HDD's (and all their other products for a start) at lower prices than other manufacturers'? Clearly they've invested less money in research thus their price tag goes down. Proper HDD manufacturers' invest A LOT of money in research. Look at WD's 10,000RPM HDD's.
If you google problems with Samsung or even WD drives and end up on a discussion forum like this one, I'm sure at the end of the thread someone will say "got a replacement" or "problems fixed". So people do report successes as well as failures. This website is a good example.
You say you've had your Samsung's for 'up to 2.5 years'. That really isn't a long time in HDD territory. I've got one WD that I've had for 4 years and a Maxtor for 7. Where I work, they're all WD drives and the computers there are all around 10 years old.