I intentionally refuse to set an email autoreply (those annoying "I'm out of the office, but your email is very important to me" messages that get spewed onto mailing lists).
Autorepliers are too dump to not spam lists, and I generally check email regardless of where I am, so it's not like important messages get dropped. Sure, less important messages might get neglected, but that should be the rule rather than an exception...
The NMC list is a perfect example of this. Someone sends a message, and (especially during conference season) it's immediately answered by a bunch of "I'm not here..." messages. Annoying. I get it. You're out of the office. Your email shouldn't care where you are...
ps. this post is the first one I've written using the fancy new WordPress Dashboard widget. It's rather barebones at the moment, but the idea is pretty cool!