I have a Seagate Barracuda IV with fluid bearings and can say it is completely silent.
As for reliability, this drive in particular has the lowest returns rate of all according to my local parts retailer (also a mate of mine, so he wouldn't lie)
I know the IBM GXP 120's have a particularly good price performance ratio but my recent bad experience with a 45gig GXP 75 has left a very bitter taste of IBM's drive products and there very poor after sales service.
But back to your question, fluid bearings are the way of the future and with no bad reports so far the technology looks sound and reliable. Martin Just trying to help, sometimes falling short, I am only human after all.