Backup your importatant data (the number of people that don't
)
If the harddrive is in warrenty its not a problem if it does die becuase the manufacturer will have to replace it.
If its not then considering most warrentys are at least 3years you've had a resonable life out of it... and drives are getting cheaper all the time.
Hard-drives are not as fragile as people think.
Of course dropping them when they're spinning is never a good idea.