Some people work in positions requiring high amounts of near constant contact. There is technology for this. One popular is the Blackberry which allows the user to no longer sit in front of the computer all the time.
If more than one person is capable of doing the job you do, then set up an email alias. Such aliases can direct a message to multiple recipients. This means should you be out of the office, then your coworker can pick up the slack. No need to set up an autoresponder.
Do you really trust the world to know you are out of town for a week? That screams Come find my house and take all my stuff while I am away. Thanks!
Finally, if I email a discussion email list and not you specifically, then do you really need to tell me that you are out of the office?