Update (2010-01-09): So turns out wpengineer.com had this figured out a while back (i.e. October 2008). Regardless, it was a good opportunity for me to dig into the WordPress core and figure out what’s going on.
…or in “proper” English: Feed Killer.
Basically, a small plugin to disable all your feeds on your WordPress install, for whatever crazy reason; we don’t judge (much). This is a result of a question by @wesbos.
There’s also a non-plugin version if you don’t want to go the plugin route (for whatever crazy reason; again, we don’t judge (extensively)). Just add the code to your theme’s functions.php file.
See below or download from gisthub.