Newbie's question about hard disk partition

[Lian Liming <lianliming@realss.com>]

Hi all,
  This is a question from a linux newbie. I am quite confused with 
linux hard disk partition.
  Someone tell me that i just need three partitions: /boot, swap and /. 
Some others tell me to separate /home from /. There is some another 
suggestion that i should separate /var form /.........

  So is there a common rule to partition the hard disk? 

  Thank you for any suggestions.