Some seem a bit harsh. One tip I heard from a seminar my wife went to was in regards to being out of the office. This person had a very effective way of dealing with emails that came in when she was away. It was very simple:

Setup an out of office email that states:

"I am away until xxx. Please resend your message after that date if it is important as I will not read those that arrive during my absense".

This person then deleted all her messages in her inbox when arriving back in the office. No email overload....

I only wish it were that easy.;)

Wow, that is pretty brutal. Effective though :) Too bad probably only 1% of the people actually read those auto-responses....