I've had nearly every brand of HD fail on me. There doesn't seem to be one that is more dependable than the others. I just had a Seagate 160 fail after 6 months, and the replacement I bought was dead on arrival!
In very general terms, the 2 platter drives seem to have more reliability and noise issues.
If you want speed, the WD Raptors are the only non-SCSI drive that delivers true speed, and they are built to last a really long time. Even so, I had a Raptor fail on me due to bad sectors. But the mechanics of the Raptor are seriously heavy duty. Barring platter problems like mine, they will outlast their usefullness.
As far as performance on standard 7200RPM ATA100/133 drives, you won't notice any difference between them. 8MB cache is a "must-have".
with any HD, the secret to reliability is adequate cooling.