I've had a few. A couple of things to note:
  • Seagate Barracuda V - Had one fail because it was in a place where its heat collected during a RAID sync. Seagate support is absolutely excellent, I shipped the drive to them, and they sent me a new one under warranty. The drives in my case now have a super quiet 120mm fan on 7v rigged up to them with cable ties. Have to say they have been very reliable since. Verdict: Heat sensitive, but recommended.
  • Samsung Spinpoint - This one is really really quiet. I like it for that. Price is very average.
  • Maxtor Diamondmax - On idle this drive is quiet, but when it is seeking it does make rather annoying rumbling noises. You get NCQ on most of them as a speed-bonus (does this make much difference?), and I find they are consistantly the cheapest per GB. I bought a 300GB SATA one last night on Komplett for 80 quid (+6 P&P) inc VAT. Can't argue with that.
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Hussein