WD Caviar 500GB
bought 2, one recently started failing. possibly because I put down a keyboard on top of the case, slight strike, might just have put it over the edge if it was reading at the time. graceful failure, wont really write to the disk anymore but I have been able to read out couple of hundred GBs sofar although the speed is reduced to 4MB/s and sometimes less. beats walking home. the failing disc was bought maybe 2008. the first disc is still working.
they have been in continuous very light duty operation more or less 16 hours a day