I'm not normally prone to linking to stuff, but this is just too good:
http://www.howtoforge.com/how-to-configure-automatic-updates-on-debian-wheezy
Explains how you can get your Debian Wheezy box to automatically update. While this is bad practice for some situations like fragile production boxes, there's plenty of spaces where automatic updates work great: single-purpose machines like your (secondary) DNS, lonely virtual private servers with your home page, etc.