Just going to throw some stats out there for people.
SSDs are actually more stable of a platform but currently have a 1/4 failure rate early on due to construction. You can get beyond this by going with higher-quality SSDs (Intel). And while they do have a theoretical set number of writes before they die, it's in the hundreds of millions. Most SSDs are rated for many years of constant use.
As for reliability of an HDD, if you really want reliable you use 1 TB or smaller drives. They have a better track-record for reliability. The 2 TB drives can be iffy if you get the wrong one (Seagate) instead of the good ones (Samsung or if you have to WD). From what I'm hearing of the current 3 TB offerings they have a pretty high failure rate and have questionable longevity.
As for how long a drive will last, Google released a white paper a few years ago about the HDDs they use in their servers and found that the general rule of thumb was if it didn't fail within the first two months then they tended to be good for five or more years. They also found that drive brand means a lot less than drive model. Which is why a 1 TB Seagate is your best friend where a 2 TB Seagate will die on you quicker than Bambi's mom.
In terms of RAID arrays... I'm of the humble opinion that anyone who uses a RAID0 array without some level of data protection is really asking for trouble. In a purely striped RAID if one drive dies you lose everything on all your drives. The best option is multiple drives and a RAID5 or RAID 10 array. It requires more drives (usually four or more with RAID10 requiring even pairings) but you get a nice level of data redundancy as well as performance.
The one thing that's nice about RAID is that if the RAID controller card dies you can replace the card and the array will function as normal. I believe it may have to be the same card, but that's the only limitation I've ever heard. I'm actually considering building my own RAID5 NAS to use as a dev/media server. I could just buy one (Synology and QNAP are the top two companies that I know of) but you can usually build your own systems for cheaper and for the sacrifice of a bit more power-usage I could have a better processor, which will be handy if I want to do any on-the-fly encoding.
Quote:
Samsung's Spinpoints are the best HDDs released so far, period. But they just sold their mechanical HDD division to Seagate
I really wish they would have had time to develop the successor to that series.
You're looking at it all wrong. It's not so much that Seagate got Samsung's HDD devision, it's that Samsung's HDD devision got a new bank-roller who is going to let them really push things. At least, that's my hope. Samsung isn't focused on drives. It's just one thing they do. HDDs is what Seagate does. With any luck, they'll bring up the level of Seagate drives over 1 TB to the point where they aren't a waste of money.