Western Digital and Seagate are the big players on the HDD space. Which one is better swings depending on which report your looking at and who was unlucky enough to have their particular branded drive fail on them. Either one would do fine.
If you want a good HDD then I agree with the above. If we're talking SSD drives it's got to be either Crucial or Samsung (as both actually manufacture the memory chips rather than just package it).
As for reliability- if your looking at traditional HDD drives you can pick up various 'enterprise' class drives quite cheaply now and they are recommended for 24 / 7 use and for important data storage as they are tested for long term stability (e.g. if you want to set up a file server or nas).